Successfully staging a mixed reality game in which online players are chased through a virtual city by runners located in the real world requires extensive orchestration work. An ethnographic study shows how this concerted achievement extends beyond the control room to the runners on the street. This, in turn, suggests the need to `decentralize' orchestration and develop support for collaboration `on the ground'. The study leads to design proposals for orchestration interfaces for mobile experiences that augment situational awareness and surreptitious monitoring among mobile participants and support troubleshooting in situations where participants are disconnected or are unable to access positioning systems such as GPS. Categories & Subject Descriptors H.5.3 [Information Systems] Group and Organization Interfaces ? Collaborative Computing General Terms Design, Human Factors Keywords Mobile & wireless games, ethnography, orchestration, GPS