It would be easy to enforce. Cast members are already roaming the area to look for unused, claimed chairs. If they see a cooler, they'll figure out who it belongs to and have it removed or else they'll remove it and bring it to lost and found. I guess you could be sneaky and fill something that doesn't look like a cooler with ice packs and drinks, but that probably doesn't happen very often.That really is a crappy policy, but not sure how it’s enforced. We own at the Marriott Ko Olina, and always bring a small (holds like 6 cans and a couple snacks) soft side cooler to the pool with drinks and sometimes snacks. Of course, we frequently order food and drinks from the servers as well (their onion rings are the bomb as are some other items, and drinks are very good too).