It's common for people to ignore parking fines until they pile up. A city might "boot" the car to disable it, or they can tow it; either way extorting the owner

It's common for people to ignore parking fines until they pile up. A city might "boot" the car to disable it, or they can tow it; either way extorting the owner to pay. Also, private parking areas contract with tow companies which incentivizes the tow companies to patrol proactively looking for violators and tow anyone without a permit or whatever. So a market was created.