The article says that this was used on cars that already had three unpaid parking fines on record.

Boots are used to ensure compliance from those who would skip parking fines.

"Parking here [inconveniences|isn't fair to|creates danger for] others, so if you leave your car here, we will make the situation worse by ensuring the alleged harm will continue longer than it otherwise would."

Yes, something something deterrence. Again, in reality, the article explains how that played out.

Proper law enforcement isn't cheap, and if it is a profit center, you don't have peace officers, you have highwaymen.

Yeah, I'm wondering the same thing.

Over here,I've never seen boots, barnacles or any such devices. Refusing to pay your ticket is just like not paying your bills. They'll send a reminder bill to your home address a few times,just in case you have forgotten or misplaced the bill/ticket, then it's over to some company that specializes in getting people to pay unpaid bills, and eventually if you still refuse you end up in court and the government makes you pay one way or another.