I suppose it's a company's perogative to do what they want (within the confines of the law.) But, contract or no, I think that if a model were to dispute it, one would have a hard time justifying the right to use content for which the model had not been compensated. And legal or not, from an ethical standpoint, I have a hard time justifying the use of the content, regardless of whether it's for promo use or on a commercial product.

If the model is high or drunk, we send them home, period. We don't pay them, and we certainly don't photograph them.

And, as Seth said, it's those sort of abusive policies that gives the industry a bad reputation. Having sex on camera isn't an easy thing to do, and if a model is making an honest effort to do his best to do a good job, and isn't high or drunk, giving them some compensation goes a long way toward the model feeling good about their experience, which translates to the model saying good things about the studio. But I guess some studios are just too shortsighted to see that.