Although I like the idea of drone for delivery services, I just think the privacy issue is too great. Not to mention drones flying low around over houses. Not a bad idea for downtown areas. If the drones fly 50 feet over the roads and not over houses, but you need to have a drone police and licensing.(like pilot licenses) for drone delivery. But people will cheat and fly the short straightest line over houses for efficiency.
The other fact is the idea of sending weapons overhead or a pipe-bomb.
The idea of a weaponized drone swarm is crazy!