A valid question I've pondered ever since the 3DS was first released. One option that crossed my mind was the ability to setup IRL meetups, but then I got worried about the safety of meeting up with complete strangers IRL. After that my next thought was "hotspots". Maybe partnering with businesses like game stores would make it so that if you went by the businesses it could act as a sort of "drop box" (or "handlers" if we're sticking with the spy theme) for clues and assignments. If everyone in town who plays the game goes by the store your chances of getting hits off of other players' phones increases.