That's one of the hot topics that come up here from time to time. The description of the mugs that you see when you buy them says that they're for that stay. Some CMs say that you can't use them at other resorts; others say you can. I read a post just recently where a guy said that he actually talked to a CM and the person told them they had just gotten a memo saying not to say anything to anyone using a mug regardless of how old it was or what Disney resort it was from. If you do take them with you, I guess there's a chance that someone will say something, but they probably won't. I don't know if it's actually right though. It would be nice if everyone at Disney followed the same policy.