Sometime back there was a demo video of a drone quad copter delivering a pizza zeroing on a mobile through which it was ordered. Now there are kits on sale for D-I-Yers to build and fly their own drones controlled even by a smart phone. The day may not be far off when this may reach pollution levels and become a hazard to life and limb.

Here is a report:

Rise of the drone hobbyists - BBC News