True, there's no way we can say "this channel is for official use only" (well, we could TRY, but I don't think we'd get very far ;) ) but I think agreeing on a channel beforehand could help coordinate a meeting (or at least help direct traffic -- "we're in line for the Mine Ride, it's light, c'mon over...")
I don't have a Talkabout handy (they belong to the travel club I'm a member of, I'll be signing out a pair for CoasterMania) so I can't throw out a suggestion right now, but as June 2nd comes around we can try to coordinate...