The combination of battery tech advances, cheap wireless comms and cheap processors has created a huge range of asymmetric risks like this. I suspect terrorists/freedom-fighters (depending on which side of which conflict you're on) will be exploring them for a long time to come - bomb-drones and remote IEDs are just the start of the development curve.
Everyone keeps calling these risks asymmetric, but we haven't seen the price of a birdshot flak cannon because there hasn't been that much of a need yet.
