That’s astonishing. He’ll pay more attention next time. But as you say, it’s a good lesson that no one is above the law.
I’ve known neighbours here who have decided that Airbnb is a golden goose and an easy way to make money (yeah right) but haven’t bothered with licenses and so on. (And here, licensing isn’t a knee-jerk anti-STR thing, it’s been around forever).
The local authorities have found them within a couple of months. That’s probably before the hosts have had the chance to recoup their start-up costs.
There are lots of things that technology can’t do yet but it can discover illegal rentals pretty easily.