I know this is from a while back but I just caught up on this thread. I agree it's hard to get any real numbers, but I do know it happens. I have a good friend that lives in Orlando and we had this conversation a while back--she said she didn't feel the need to look for an apartment complex with a pool, because they could just go over to one of the resorts and use the pool there. When I told her that wasn't allowed, she said "Well we're annual passholders." Which apparently she felt gave her the right to use the pools. We had the same conversation when she bought
DVC. Apparently they and some of their friends do it all the time and while I like her it drives me crazy that she'd feel entitled to use what other people are paying for.
We were there last November 1-10 and were able to swim several days, even after a cold front had come through at the beginning of our trip. Not sure about other pools, but the Dig Site at CSR was never crowded, and SAB was busy but not overly crowded.