Looks like my article, Self-Defense Against Robots and Drones (written with Zak Colangelo) isn’t a minute too early. ArsTechnica reports Man shoots downs neighbor’s hexacopter in rural drone shotgun battle.
The parties in Joe v McBay differ as to where the drone actually was when it got shot. Plaintiff says it was on his land, defendant says the GPS data shows it wasn’t. The Judge from the Stanislaus County Court Small Claims Division didn’t care:
Court finds that Mr. McBay acted unreasonably in having his son shoot the drone down regardless of whether it was over his property or not
We don’t agree in our article that the drone’s location is irrelevant. If the drone was not on the defendant-shooter’s land, then he ought to be liable for the damages. But whether he should be liable if the drone was trespassing is a surprisingly complicated question that we address at some length in our article. It depends in large part on what the shooter reasonably thought the drone was doing, and whether the act of shooting the weapon, or any subsequent drone crash, would put anyone else at risk.
Basically, in an urban area it will almost never be reasonable to shoot down even a trespassing drone unless it clearly threatens physical harm to a person or perhaps very major property damage. In a rural area where the dangers of errant shots and crashing drones may be much less, many other factors come into the calculus of reasonableness, including whether it reasonably appears that the drone may be on a spying run, and how valuable the drone looks.