As expected, drones are becoming a big thing in the USA, and there are a bare minimum of 63 active sites in the country - hard to say, because the military has a bunch, obviously, as does the Border Patrol, and there isn't any way of telling, at present, what types of drones are up there nor how many there are. If you happen to be in Seattle, their police department is an active user, so you might want to wave - one finger at a time.