To clarify some of the discussion, there are two separate regulatory regimes at play here. Navigable airspace is regulated by the FAA and the FAA has recently

To clarify some of the discussion, there are two separate regulatory regimes at play here. Navigable airspace is regulated by the FAA and the FAA has recently begun to enforce its rules for UAS or drones (see tensafefrogs's comment). The FAA's view is that the difference between RC and a UAS/drone is whether the operator gets paid. They mostly ignore the RC community. Then there is a state/local regulation of reckless behavior in general. This is not related to flying, per se. It is related to endangering others. The pattern of prosecution is the feds going after operators who are getting paid for violating the rules for aircraft (any aircraft piloted or not must maintain separation from buildings, etc.) and the state/local authorities going after RC operators who endanger others through recklessness. All in all, it seems like we're moving towards a rational system where RC operators can play in safe spaces and eventually we'll have licensing and regulation of commercial operators to work in more challenging environments.