I can tell you we were staying at BWV and taking a walk around the lake on a Friday night and Cars was being shown at the beach. There were lots of lounge chairs on the beach, with people coming and going . My DD wanted to stay and watch the movie so we saw the last 1/2 hr or so. I would imagine guests would get an activities list at check-in or a schedule would be posted somewhere in Beach/Yacht club hotels.
The movies are shown on the beach that is accessible by the public at large. Anyone passing by can view the huge screen, so it's not limited to just the guests of the BC.