Oh, you wont do it? then you arent in the scene and dont get paid. Goodbye.
Siskel and Ebert said this back in the early 1980s. If a girl is not willing to do nude scenes, she is “out the door”, and there are dozens of other girls waiting in the wings to take her spot.
I remember this story. If they didn't agree to the shoot (and surely, some didn't), they'd have to pay their own way back to whatever town they flew in from.
I know a guy who passed up a day at his sales gig and was told to strip.