It is what it is. Not much you can do to prevent people from chatting in a a "local" room. You can get agitated if you want, but it really doesn't change anything. I don't think it's a matter of AOL not caring, either. There just not much they can do about it realistically.
I think the rooms that trenchik has setup seem like a decent alternative. The other would be to monitor the Philidelphia room and invite people to a private chat room (filtering out the bots and people from California).