I am actually surprised that we haven't seen assassinations by drones yet (I mean non USAF drones). Consumer drones can't carry a big payload, but I'd guess they can carry enough explosive to kill someone. And even someone super protected like a US president would be helpless facing 5 drones travelling at 50km/h coming his way. I guess most terrorists are dumb and all recent attacks in the west have shown to be low tech, but I'd rather not count on that to protect us.
But in the US it's fine, since the drones have to carry a license number. That will protect us!