I wonder how difficult it would be to have a circuit on a drone that could detect the presence of ATC radars and such and respond (like, reverse course and land). I would say act as a kill switch but we'd just trade the problem of idiots flying too close to planes for idiots seeing how close they can get before it falls out of the sky, points for what it hits, etc.
Of course, it would be nice if we could establish a perimeter around airports that would kill the drones but also allow a safe (for others) place for it to fall. Hey, fly too close, lose your toy.
You know, we've had "drones" for decades. Radio Controlled (RC) planes. Even toy rockets to launch in the air. But, only recently it seems, apparently after strapping cameras to them and calling them drones, have we had this problem with people being stupid enough to fly them into aircraft.