See Rule #4
Already been adequately answered to. I'll add to it tho that the drone will probably be data linked to all other friendly assets in the war zone so it wont be slaved to only what its own sensors can input.
If you have a drone armed to the teet flying above your troops and someone manages to spoof its gps signal so that it accidentally bombs your own troops AUTONOMOUSLY then I'd call that a victory for the enemy. And your own troops will riot the instant first case like this happens. Not to mention the danger of this happening even without enemy intervention, through programming error or sensor defect. A drone can't use its own brain when it sees everything doesn't quite add up (such as seeing friendly troops a
t the dropzone).
Except that GPS wont be its only guidance tool. TERCOM and DSMAC is already part of the Tomahawk cruise missile guidance package so there is no doubt future automated drones will have at least that. In any event the drones software will be written to hold on to ords should there be any inconsistencies. Besides many of the drones ords will no doubt be riding laser's guided by ground troops. I'd bet the drones would be, if anything, less prone to killing friendlies then manned systems are.
But the real hindrance is public perception in a country where every fat arse civilian puke thinks they should have a say in the ROE's of every war their neighbors kid is fighting. They have no stake or children involved in the fight so its easy for them to poke the air with a finger and say how inhuman drones are, most of all pre-programmed ones. THEY have been programmed into believing its more humane when an actual human pulls the trigger and pushes the button. Or they have convinced themselves theres better ways then violence to deal with an enemy who has no "Rules Of Engagement" or rules of any humane kind.
I hope we build Terminators and send them over to murder every terrorist they can find. But thats just me.