Certainly chair saving is a rampant problem at all resorts. I don't believe posting a sign will have much impact- rude people tend to ignore them! At the Hyatt Maui this March, chairs were saved from 9am and it was kind of riduculous. Finally I noticed a note stuck on a few towel covered chairs that read something like- chair saving is not allowed, if someone is not occupying the chair within the next hour, the towel will be removed. Of course this too will only work if it is enforced. So at busy times if someone went around with these notes once an hour, then maybe more chairs would be freed up.