[hnbad]

I'd imagine as stealth goes, driving up to someone's house is a much more subtle way to deliver a grenade than launching a drone that goes EEEEEEEEEEEE all the way as it is hastily steered to its destination while the operator attempts to avoid bumping into a street lamp and then fiddles with the controls to drop the grenade in such a way it actually detonates before the victim figures out what's going on.

Drones are hardly even a daily occurence let alone frequent enough not to catch anyone's attention. Cars on the other hand are everywhere.