http://blogs.computerworld.com/security/20593/civilian-drones-vulnerable-hackers-can-be-hijacked-used-missiles

This is how Iran claims it  grounded and captured US Drone few months back

The same old story. No matter what it is, a PS3, X-Box or Drone someone somewhere will find a way to hack it. Anyone who says something is Unhackable is a red cape to a bull and will bring the hackers out in their droves to be the first to prove them wrong. Why a country needs 30,000 drones flying around their airspace is stupidity. Forget the terrorist angle, it's their own people they will be watching.

The US government is getting somewhat worried about RC flyers messing around with FVP Today a civilian can do almost everything a drone can do except stay airborne all day, use satellite communications and fire missiles. How long until they ban them under privacy laws?

Stu