I don't think she got voted out for being annoying. I think that she was a liability to all sides. She was simply too dangerous to have around. On the Ponderosa clips she mentions that she told her tribemates that Taj had the idol and they didn't believe her. If that is true (which it likely is , because unless someone let erinn in on the tree mail holding the idol how did she know that little tidbit last night) Sierra was playing whatever side served her at the moment. It was simply too hard to know how long she would follow an alliance with you. She was ready to cross her old tribemates (rightfully so). She possibly had something going with Erinn (she would not write her name down, and was not totally in with Coach's minion). She had a lot going on out there that made her dangerous to keep around. It all goes back to how much each remaining Survivor knows about the dealings going on out there and what secrets they are interested in keeping. Sierra could cause trouble with her mouth. They got a great view of that last night when she reamed out Coach and Debbie. I think they let her go because of the trouble she could cause, not because they wanted peace out there.