Director Amy Berg (L) and Dixie Chicks' singer Natalie Maines pose at the gala presentation for the film "West of Memphis" at the 37th Toronto International Film Festival September 8, 2012.
REUTERS/Brett Gundlock (CANADA - Tags: ENTERTAINMENT) 

Dixie Chicks' singer Natalie Maines poses at the gala presentation for the film "West of Memphis" at the 37th Toronto International Film Festival September 8, 2012.
REUTERS/Brett Gundlock (CANADA - Tags: ENTERTAINMENT) 

Musician Natalie Maines of the Dixie Chicks arrives at the 29th Annual ASCAP Pop Music Awards in Hollywood, California April 18, 2012. The awards are given out by the American Society of Composers, Authors and Publishers. REUTERS/Jason Redmond (UNITED STATES - Tags: ENTERTAINMENT) 

Musician Natalie Maines of the Dixie Chicks performs Carly Simon's "That's The Way I've Always Heard It Should Be" at the 29th Annual ASCAP Pop Music Awards in Hollywood, California April 18, 2012. The awards are given out by the American Society of Composers, Authors and Publishers. REUTERS/Jason Redmond (UNITED STATES - Tags: ENTERTAINMENT) 

Natalie Maines (L), lead singer for the band "Dixie Chicks", her husband actor Adrian Pasdar (2nd R), and their sons Jackson (2nd L) and Beckett (R) pose at the premiere of "Real Steel" in Los Angeles October 2, 2011. REUTERS/Danny Moloshok (UNITED STATES - Tags: ENTERTAINMENT) 

Natalie Maines, lead singer for the "Dixie Chicks", poses at the premiere of "Real Steel" in Los Angeles October 2, 2011. REUTERS/Danny Moloshok (UNITED STATES - Tags: ENTERTAINMENT) 

RNPS IMAGES OF THE YEAR 2007 - ENTERTAINMENT - Dixie Chicks Emily Robison (L) and Martie Maguire (R) joke with Natalie Maines during their performance at the opening night of the Nokia Theatre L.A. Live in Los Angeles October 18, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

Emily Robison performs with the Dixie Chicks at the opening night of the Nokia Theatre L.A. Live in Los Angeles October 18, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

Martie Maguire performs with the Dixie Chicks at the opening night of the Nokia Theatre L.A. Live in Los Angeles October 18, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

Natalie Maines performs with the Dixie Chicks at the opening night of the Nokia Theatre L.A. Live in Los Angeles October 18, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

The Dixie Chicks (from L-R) Emily Robison, Natalie Maines and Martie Maguire perform at the opening night of the Nokia Theatre L.A. Live in Los Angeles October 18, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

The Dixie Chicks (from L-R) Emily Robison, Natalie Maines and Martie Maguire perform at the opening night of the Nokia Theatre L.A. Live in Los Angeles October 18, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

Dixie Chicks Emily Robison (L) and Martie Maguire (R) joke with Natalie Maines during their performance at the opening night of the Nokia Theatre L.A. Live in Los Angeles October 18, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

Emily Robison, a member of the country music group 'Dixie Chicks' poses at the premiere of the documentary film by director Peter Bogdanovich "Runnin' Down A Dream: Tom Petty and the Heartbreakers" at Warner Bros. studios in Burbank, California, October 2, 2007. REUTERS/Fred Prouser (UNITED STATES) 

Singer Natalie Maines of 'The Dixie Chicks' poses with her son Slade as they arrive as guests at the premiere of "Pirates of the Caribbean At World's End" in Anaheim, California, May 19, 2007. REUTERS/Fred Prouser (UNITED STATES) 

The Dixie Chicks (L-R) Emily Robison, Natalie Maines and Martie Maguire pose with their Grammys at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. The group won the Record of The Year, Song of the Year and Best Country Performance by a Duo or Group with Vocal for "Not Ready to Make Nice"; and Best Country Album and Album of the Year for "Taking The Long Way". REUTERS/Mike Blake (UNITED STATES) 

A publicist puts an end to a photo shoot with the Dixie Chicks (L-R) Emily Robinson, Natalie Maines and Martie Maguire as they pose with their Grammys at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. The group won the Record of The Year, Song of the Year and Best Country Performance by a Duo or Group with Vocal for "Not Ready to Make Nice"; and Best Country Album and Album of the Year for "Taking The Long Way". REUTERS/Mike Blake (UNITED STATES) 

The Dixie Chicks, (L-R) Emily Robinson, Natalie Maines and Martie Maguire, pose with their five Grammys at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. The group won the Record of The Year, Song of the Year and Best Country Performance by a Duo or Group with Vocal for "Not Ready to Make Nice"; and Best Country Album and Album of the Year for "Taking The Long Way". REUTERS/Mike Blake (UNITED STATES) 

The Dixie Chicks (L-R) Emily Robison, Natalie Maines and Martie Maguire pose with their Grammys at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. The group won the Record of The Year, Song of the Year and Best Country Performance by a Duo or Group with Vocal for "Not Ready to Make Nice"; and Best Country Album and Album of the Year for "Taking The Long Way". REUTERS/Mike Blake (UNITED STATES) 

The Dixie Chicks (L-R) Emily Robinson, Natalie Maines and Martie Maguire pose with their Grammys at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. The group won Record of The Year, Song of the Year and Best Country Performance by a Duo or Group with Vocal for "Not Ready to Make Nice"; and Best Country Album and Album of the Year for "Taking The Long Way. REUTERS/Mike Blake (UNITED STATES) 

Natalie Maines (C) gives the peace sign after the Dixie Chicks won Album of the Year for "Taking The Long Way" at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

The Dixie Chicks accept the award for Album of the Year for "Taking The Long Way" at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

Natalie Maines (L) and Emily Robinson from the Dixie Chicks accept the award for Album of the Year for "Taking the Long Way" at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

The Dixie Chicks, Martie Maguire (L), Natalie Maines (C), and Emily Robinson, accept their award for song of the year at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

The Dixie Chicks, Martie Maguire (L), Natalie Maines (C), and Emily Robinson, accept their award for song of the year at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

Seal (L) and Burt Bacharach (2nd L) present the Song of the Year award to the Dixie Chicks at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

Natalie Maines from the Dixie Chicks accepts the Song of the Year award for "Not Ready to Make Nice" at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

Natalie Maines of the Dixie Chicks performs "Not Ready To Make Nice" at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

Natalie Maines of the Dixie Chicks performs "Not Ready To Make Nice" at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Lucy Nicholson (UNITED STATES) 

The Dixie Chicks arrive at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

Martie Maguire of the Dixie Chicks arrives at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

Emily Robinson from The Dixie Chicks arrives at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

Natalie Maines from The Dixie Chicks arrives at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

The Dixie Chicks arrive at the 49th Annual Grammy Awards in Los Angeles February 11, 2007. REUTERS/Mario Anzuoni (UNITED STATES) 

The Dixie Chicks perform during a concert to honor Don Henley as the 2007 MusiCares Person of the Year in Los Angeles, February 9, 2007. REUTERS/Chris Pizzello (UNITED STATES) 

Natalie Maines of the Dixie Chicks performs during a concert to honor Don Henley as the 2007 MusiCares Person of the Year in Los Angeles, February 9, 2007. REUTERS/Chris Pizzello (UNITED STATES) 

Natalie Maines, one of the members of "The Dixie Chicks", poses as she arrives at the 2007 Musicares Person of the Year dinner honoring musician Don Henley in Los Angeles February 9, 2007. Musicares, a charitable foundation, provides musicians in need with financial and medical assistance. REUTERS/Fred Prouser (UNITED STATES) 

Members of "The Dixie Chicks" (L-R) Emily Robinson, Natalie Maines and Martie Maguire pose as they arrive at the 2007 Musicares Person of the Year dinner honoring musician Don Henley in Los Angeles February 9, 2007. Musicares, a charitable foundation, provides musicians in need with financial and medical assistance. REUTERS/Fred Prouser (UNITED STATES) 

Members of "The Dixie Chicks" (L-R) Emily Robinson, Natalie Maines and Martie Maguire pose as they arrive at the 2007 Musicares Person of the Year dinner honoring musician Don Henley in Los Angeles February 9, 2007. Musicares, a charitable foundation, provides musicians in need with financial and medical assistance. REUTERS/Fred Prouser (UNITED STATES) 

Singer Natalie Maines of the 'Dixie Chicks' accepts the American Civil Liberties Union of Southern California Bill of Rights award on behalf of the 'Dixie Chicks' at the organization's Bill of Rights dinner in Beverly Hills, California December 11, 2006. The 'Dixie Chicks' were honored for their work to help preserve civil liberties and civil rights. REUTERS/Fred Prouser (UNITED STATES) 

Television host and comedian Bill Maher gestures as he speaks before presenting the American Civil Liberties Union of Southern California Bill of Rights award to singer Natalie Maines of the 'Dixie Chicks' at the organization's Bill of Rights dinner in Beverly Hills, California December 11, 2006. The 'Dixie Chicks' were honored for their work to help preserve civil liberties and civil rights. REUTERS/Fred Prouser (UNITED STATES) 

Television host and comedian Bill Maher (L) presents the American Civil Liberties Union of Southern California Bill of Rights award to singer Natalie Maines of the 'Dixie Chicks' at the organization's Bill of Rights dinner in Beverly Hills, California December 11, 2006. The 'Dixie Chicks' were honored for their work to help preserve civil liberties and civil rights. REUTERS/Fred Prouser (UNITED STATES) 

Singer Natalie Maines, a member of the singing group 'Dixie Chicks", arrives at the American Civil Liberties Union Bill of Rights dinner in Beverly Hills, California December 11, 2006. Maines accepted an award honoring the 'Dixie Chicks' at the event. REUTERS/Fred Prouser (UNITED STATES) 

Singer Natalie Maines, a member of the singing group 'Dixie Chicks' arrives at the American Civil Liberties Union Bill of Rights dinner in Beverly Hills, California December 11, 2006. Maines accepted an award honoring the 'Dixie Chicks' at the event. REUTERS/Fred Prouser (UNITED STATES) 

Singer Natalie Maines, a member of the singing group 'Dixie Chicks' arrives at the American Civil Liberties Union Bill of Rights dinner in Beverly Hills, California December 11, 2006. Maines accepted an award honoring the 'Dixie Chicks' at the event. REUTERS/Fred Prouser (UNITED STATES) 

Actors Christian Slater (L) and Sharon Stone introduce the Dixie Chicks at the 2006 American Music Awards on November 21, 2006 in Los Angeles. REUTERS/Mario Anzuoni (UNITED STATES) 

Natalie Maines of the Dixie Chicks performs 'Easy Silence' at the 2006 American Music Awards on November 21, 2006 in Los Angeles. REUTERS/Mario Anzuoni (UNITED STATES) 

The Dixie Chicks perform 'Easy Silence' at the 2006 American Music Awards on November 21, 2006 in Los Angeles. REUTERS/Mario Anzuoni (UNITED STATES) 

The Dixie Chicks (L to R) Emily Robison, Natalie Maines and Martie Maguire arrive at the 2006 American Music Awards in Los Angeles November 21, 2006. REUTERS/Lucy Nicholson (UNITED STATES) 

The Dixie Chicks (L-R) Emily Robison, Natalie Maines and Martie Maguire arrive at the 2006 American Music Awards in Los Angeles November 21, 2006. REUTERS/Lucy Nicholson (UNITED STATES) 

Cast member Natalie Maines displays a chicks paws tattoo on her foot at a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

Cast member Natalie Maines gestures at a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

Cast member Martie Maguire (L) gestures next to co-star Natalie Maines at a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

Cast member Natalie Maines (R) gestures next to co-star Martie Maguire at a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

Cast member Emily Robison smiles at a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

Cast member Martie Maguire gestures at a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

Cast member Natalie Maines (C) gestures, as co-stars Martie Maguire (L) and Emily Robison watch at a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

Cast member Natalie Maines laughs at a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

Cast members Martie Maguire (L), Natalie Maines (C) and Emily Robison pose after a news conference for the documentary "Dixie Chicks: Shut Up and Sing" during the 31st Toronto International Film Festival in Toronto September 13, 2006. The festival runs from September 7 until September 16. REUTERS/Mario Anzuoni (CANADA) 

The Dixie Chicks (from L-R) Emily Robison, Natalie Maines and Martie Maguire arrive for the gala premier of their new movie "Shut Up and Sing" at the 31st Toronto International Film Festival in Toronto September 12, 2006. The festival runs from September 7 to 16. REUTERS/J.P. Moczulski (CANADA)