First of all, exactly what are the restrictions on that ride? I've not ridden a Rotor myself (which is what we're talking about here...not a Gravitron, not a Round-Up, not a UFO), but I have seen one in action and first of all I don't think footwear would have been an issue, and second, I still don't understand how she managed to get her foot caught. Until we understand exactly how the incident happened, there really isn't any way for us to evaluate whether the park has any valid defense in this case.
Also, a word about the Super Round-Up, SOB Fanatic, as I had a minor altercation on that ride a couple of seasons ago at Americana. I got yelled at because, during the ride, I lifted both feet, bent my legs, and put my feet on the back of the ride tub. The poorly trained operator on duty that day (I'm CERTAIN it wasn't you) was unaware that bending your knees on that ride and either lifting your feet or lowering your body is a perfectly valid tactic for preventing the onset of G-LOC on that ride. In fact, some parks make certain to tell riders about that when the ride starts.
--Dave Althoff, Jr