Hi Phatboy,
No, there is typically not a "contract" signed. There is a model release, it does not release the male talent or the company to do whatever they please with the girl, it releases them to use the content in videos, internet, etc.
Typically this release is signed and the ID's are taken before the video is done. Sure, she knew that she was going to get ass fucked with a dick in her pussy at the same time, but shouldnt companies have a "safe word," for example, let's say the safe word was Orange. They tell the girl if there is a problem say the word Orange, then the male talent knows to back off. In bondage photography this is widely used. Vicky told me on the phone that she asked them to stop and that she was trying to raise up off the guy that was on the bottom and he put his arms around her waste holding her down. This is porn, yes. But even porn should have rules and be civilized. This woman had to go to a doctor, do you think she enjoyed it? I think not.

<img src="/ubbthreads/images/graemlins/angrya.gif" alt="" />