Dr. Evil, I'm inferring that if the cameras were turned off, there might not be any raw footage of the crucial moments. Also I'm guessing that if any of the cameras were on, it would then be a simple matter to destroy the evidence before any authorities could seize it.
Not knowing anything about this performer other than what's posted above, I'd say her responsibilities include reading and understanding her contract; not signing anything that prevents her from negotiating or setting limits; being clear about setting those limits; and of course being willing to walk away from the industry if she's unable to deal with the emotional wreckage that often goes hand-in-hand with trading one's sexuality for money.
My reading of this situation is that she was "persuaded" to give in to the anal invasion the same way a falsely accused person might be "persuaded" to give a confession, if they're outnumbered and feel alone, their wishes are not being respected or even heard, and they are tired of fighting and just want their current predicament to end, albeit temporarily. The pressure to "go along" can be overwhelming in certain situations in life, for either gender.
I can also see why she, having lost the battle during the shoot, might want to think of ways to win the larger war, such as suing, getting her typical porn-star recognition on the box cover, or whatever else.
I think it's worth asking why all the men in the room persisted with the anal sex even though she had made it clear that she didn't do anal.