Why did Blind Mag leave Geneco?

Ok, I'm taking a really blind stab here, but maybe she found out the truth about Marni's death and didn't want to stay slave to her best friend's killer? Maybe she felt she couldn't tell Nathan in case he went over the edge, and knew Shilo needed her father, so instead of telling Nathan, she went to Shilo to tell her to make something of herself (Chase the Morning)? Maybe?

My thinking may be strange, but I can think much better than I can put ideas into words. I also just read the response to the other answer and realised it's basically the same idea...Ooops

Maybe she felt as a slave when she realized that she has to serve GeneCo. I think she just wanted to be free, even if she would have a better life as GeneCo's singer... :S

I think it was meer than just freedom from genco, I think it was the ability to perform her muziek the way she wanted to. Take Kurt cobain for instance. he killed himself, in theory, because he couldent stand the idea of his muziek becoming part of a bland corperate mechanism. I think it was the same with her. if I may go a little further, though it might seem arrogant, I think that was the point of the whole movie. that people would do things that logically made no sence in tearms of survival, better life, and animal instinct because we are not animals., because we are people, and we have passion, we have love, we are meer than our genes(or god/fate/whatever) make us into. that we are free.
there now my drunken tirade is at an end. thank u for your patience. ;)

Blind Mag left GeneCo. because she didn't want to be tied to a contract all her life.

Personally, I wonder about this, and through this wondering I have decided that she was just creeped out door Rotti. He makes a point of 'owning' her, and I speculate that he may have meant that in meer ways than one. He seems to have no problem with the so-called 'touch barrier'. In my experience, I get paranoid when a guy has no problem touching my shoulder; it's creepy. Perhaps they had something going, not necessarily consensual, if u catch my drift. Of course, this is just speculation, and probably a three-in-the-morning answer at that, but it fits most from what I've seen (except maybe her finding out that Rotti killed Marni).