I think that I would be pretty pissed if somebody did that (made casts of a figure that I had made). Of course, I don't really sculpt original pieces or anything like that, so I don't have anything to be worried about, however, if I had put a lot of time into sculpting something and I sold it to a guy who, in turn, made molds of it and "mass produced" it, I don't think I would be too happy.