Take advantage of parking garage grace periods
Most parking garages around the world have what is called a grace period. This means if you do not find a parking spot within a 5-10 minute period, you can leave the garage without paying. This person notes that you should take advantage of these said grace periods and that not all garages require you to get a ticket.
They further note that this is the simplest way to work the system when no ticket is required. This way they cannot prove when you entered the garage. I do think this hack could work in certain cases. Good luck trying.