This article explores the notion of cheating in location-based mobile applications. Using the popular smartphone app Foursquare as main case study, it addresses the question if and how devious practices impact the boundaries between play and reality as a negotiated space of interaction. After establishing Foursquare as a prime example of the gamification phenomenon and pervasive gaming, both of which require us to rethink notions of game and play, it is argued that cheating in location-based mobile applications like Foursquare has the potential to challenge not just the boundaries of play, but also our playful identity.