Radio controlled aircraft used to be just hobby aircraft. But in the past few decades, military versions of UAV's have proven that they can be used for lethal purposes. With terrorism on the rise, and as the number and type of UAV's growing hugely (I mean, they will have unmanned full sized fighter planes soon, for real!), the US government has correctly decided to regulate UAV's. The hobby lobby (couldn't resist that), has done a stellar job working with the FAA in protecting the venue of the RC hobbyists. One of the ways to distinguish a "UAV" from an RC hobby aircraft is "purpose". Am I enjoying my hobby, or am I taking pictures of houses for a Real Estate company. Moving away from strict hobby use to Commercial or Military use redefines the RC aircraft from "hobby use" to "UAV", under a different set of laws, even if it is the same plane. Hobbyists are limited to 400', line of sight, weight restrictions, no-flyover-people, and must contact the airport if flown within 3 miles of an airport. By following these rules, we hobbyists protect our hobby even in the face of more strict UAV laws. And even we hobbyists get "NOTAM" alerts, shutting us down for a few hours when the POTUS comes to town.