Towing services are just like posting a sign that says, "if you walk on this forbidden sidewalk, then we have the right to steal your shoes, and you have to pay us hundreds of dollars to get them back," amirite?

No... they'd only steal your shoes if you left them there, blocking the path of people who have paid to walk there.

There is often a good reason not to be able to park in certain places. Or would you rather be able to park in the fire lane?