(bribe a dealer) and might get "lucky". However, since the dealer (at the Gold Coast at least)would be risking his job, I'm not sure they would do it for a "stranger". Given my understanding of recent events with a few of the "suits" in the poker room, I don't think buying the $2 chips at the poker poduim will be likely any time soon either.
As for your assertion that "many of the regular casino cages don't have them", how do you suppose they get from the drop box back to the poker room? The steps between drop box and poker room involve the count room (which is part of the "cage") and the cage itself. They sit in the cage until the poker room orders a fill that includes the drop chip denomination.