The US does patrol the borders with UAVs, and has been for a long time. They don't even try to hide it... http://files.air-attack.com/MIL/predator/predator_dh

The US does patrol the borders with UAVs, and has been for a long time. They don't even try to hide it... http://files.air-attack.com/MIL/predator/predator_dhs.jpg http://files.air-attack.com/MIL/predator/predator_dhs.jpg