Terrorists and rebels the world over have embraced the radio-controlled aircraft hobby. Over the past few years, hobbyists have used off the shelf vidcams and transmitters, mounted on large radio-controlled aircraft, to build their own UAVs. Even American troops have done this, when there was a shortage of official issue UAVs for them. Terrorists in Iraq, Afghanistan, Pakistan and the Philippines have been discovered using their home-made UAVs to scout out the enemy. The word got around via the Internet, and all of these countries already had a small local hobbyist community using radio controlled aircraft. While the hobbyists were usually not willing to help terrorists, the equipment dealers would sell to anyone, and the hobbyists are always happy to show off their creations, and how they did it. So there's no real barrier to terrorists acquiring this useful reconnaissance technology.