She's not going for the mental defect (too hard to pull off these days). She's going for self defense, which is such a crock of shit.
http://www.washingtonpost.com/wp-dyn/content/article/2010/03/31/AR2010033102109.html?sid=ST2010033002114
As Erica already wrote, Cara LIKED rough sex... REALLY rough sex. Any marks on her neck would be there because she asked for it (I mean that quite literally). It's going to be hard for her to prove that he attacked her. There's probably dozens of people who could testify she liked auto-erotic asphyxiation and being on bottom of BDSM.
And then there's the issue of establishing character... She doesn't even have visitation right to see her own kids. Rumor has it that she was convicted of assaulting her own husband. That's right - A history of domestic violence.
There's also the small issue of her being quoted in the Washington City Paper as saying "He told me to do it" when she ran out of the room. Oh, and of course the part where she writes "I love u Dirk, but sometimes I want to kill u" on her facebook page the day before she shot him in "self defense".
Cara Cottle is loud, aggressive and stupid. She's going to get stuck in her own web of stupidity, violence and lies.