Drones: Flight in 3d open space is not a hard problem for machine learning. Indiscriminate Visual Targeting: Not all that hard a problem for machine learning.

Downvote me if you will, but I freely admit that I am scared of drones with guns. Either as an invading force, or as an attack from terrorists. A machine doesn't have to be smart to shoot at anything that moves or has a heat signature.

Edit: Drones with chainsaws however are just plain badass (and potentially useful for tree trimming).