Hitchers is a game for mobile phones that exploits cellular positioning to support location-based play. Players create digital hitch hikers, giving them names, destinations and questions to ask other players, and then drop them into their current phone cell. Players then search their current cell for hitchers, pick them up, answer their questions, carry them to new locations and drop them again, providing location-labels as hint to where they can be found. In this way, hitchers pass from player to player, phone to phone and cell to cell, gathering information and encouraging players to label cells with meaningful place names. A formative study of Hitchers played by 47 players over 4 months shows how the seams in cellular positioning, including varying cell size, density and overlap, affected the experience. Building on previous discussions of designing for uncertainty and seamful design, we consider five ways of dealing with these seams: removing, hiding, managing, revealing and exploiting them. This leads us to propose the mechanism of a dynamic search focus, to explore new visualization tools for cellular data, and to reconsider the general relationship between 'virtual' and 'physical' worlds in location-based games.