[acdha]

You’re definitely right that it’s not unprecedented - and as Americans know all too well, even a single gunman can produce a hundred casualties – but there is something worrisome about further reducing the skill threshold and increasing the likelihood of the attacker getting away cleanly.

I think the main difference is precision and anonymity - mortars are noisy and would attract attention, but a drone fits in a backpack and there’s no obvious connection between the launch site and the targets, so things like ballistics analysis and “shot spotter” systems are less effective. If there’s, say, a hotel or apartment building you’re going from needing to check the roof to needing to worry about every window even on the non-facing sides.