I think the casinos are not as quick to backroom you as they used to be, due to the lawsuits and publicity of the past few years. I am not speaking from experience though as I only play several hundred hours a year in vegas and have never come close to being backroomed. I know my plan would be to try to get to the door as quickly and nonconfrontationally as possible. If they tried to detain me, I would advise them that i was aware of my rights and the law regarding illegal detention, preferably stating such to a supervisor or someone other than the security goon.
This is a field that I know I would like to know more about. Hopefully some of the longer time Vegas players will share their experiences.