Re: Soon-
Not to mention taking them out of the sky to grab the item(s) being delivered.
Apparently in parts of NZ there are people who follow courier vans around the ‘burbs in the day then they swipe the parcels from letterboxes and off doorsteps.
Autonomous flying drones carrying goods are an obvious hijack target. If you make the high pressure jet full of a dark coloured sticky liquid you can avoid being fingered by the cameras as well.
You could mount it on the back of what the Yanks call trucks for fast recovery of the item and getaway. Or in the back of a van with a retractable roof like a Victorian disappearing gun. Further NZ connection: at the head of the Otago harbour (Dunedin) in the middle of the Royal Albatross breeding colony there is a still working disappearing gun and they run separate tours to it if giant seabirds are not your thing.