Here in Tampa, our overnight radio jock likes to give his audience clues as to the location of a particular pay phone. If you answer the phone when he calls, you win tickets, usually for a sold out headlining concert.
Yeah, it could also be used during scavenger hunts ,so if someone finds an item, then they are directed to the next payphone within a certain time limit and whoever gets their first answers the phone and they get clues for the next item and so on and so on.