Guy kept parking in front of a dropped kerb access to/from the courtyard of my apartment building.
Despite numerous warnings, he kept doing it.
It was almost impossible to get my bike into the courtyard.
After a long time and many many warnings, he still kept doing it and he was the only person who would park there.
I had a little tool that would remove the valve stem from the inside of the pressure valve (the one you use for inflation of a tyre)... so I would remove two of them in the middle of the night when no-one was looking.
He would come down to two deflated tyres, without the stems to hold any pressure in so he couldn't just pump them up and he only had one spare.
Despite doing this on about 5 occasions... he STILL kept parking in the same spot.
Ended up using superglue to stick a bunch of paper on his windscreen... the paper sheets were just normal A4... but the superglue on the windscreen spelled out a certain 4 letter C word that is banned on these forums... so that when he tried to pull the paper off, it would leave a massive swear word in very easy to see letters across his whole windscreen.
Then and only then, did he finally get the message and stop parking there.
Superglue does not come off a windscreen... he had to get the screen replaced... it was quite entertaining for a few days, even after he managed to get most of the paper off, he still had these big letters that looked like a distortion in the glass.
Almost amusingly... only about 2-3 weeks later, the local council changed the parking regulations for that street and no-one was able to park there at any hour of the day due to updated bus routes.