Ok, this all happened more than 30 years ago, so it was before cars had steering wheel locks and most people then were a bit more respectful of others …and were expected to be.
I worked at the local public library, and it had reserved parking for senior employees behind the building. The spots were clearly marked as reserved, and there was ample parking available nearby. Despite the signs, customers for nearby businesses would sometimes park in the library’s reserved spots or park so that the library’s employees were blocked in couldn’t get out of their parking spots.
My boss at the time was a bit of a take charge type, so rather than call the police to have the offending vehicles towed she employed some self-help. BTW, we’d first check with all of the employees and patrons then in the library-(it was a small library) before taking action to make sure we wouldn’t be inconveniencing any of our own people.
Anyway, my boss would have several of the able-bodied assistants put the offending car in neutral and push it into a low traffic side street (most parked cars were left unlocked). We’d place the car so it blocked the street diagonally, put the transmission in park (or in gear if it was a manual transmission) and set the parking brake, take a stick and wedge it so the horn was honking, and then lock all the doors on the offending vehicle. My boss would then call the police and report the abandoned car.