Yeah after seeing what tiny DIY "racing quadcopters" can do I am really amazed that we haven't seen a swarm of them used for a non-state-actor ("terrorist" or otherwise) attack.

These things are way faster and more maneuverable than in the slaughterbots video. Those were like birds. These are like hummingbirds on meth.

They are totally noncommercial hobbyist/DIY products -- there's no firmware lockdown or geofencing like on the commercial products. You can fab the PCBs yourself.

Firmware controls on drones were always a silly strategy anyways.