Over a summer I lived in "intern housing" at a university in the DC area. They wanted $150 for parking for 2mo, yeah, nope. A little bit of research told me that the parking services were a separate entity from the school and that the school would put a hold on my student account and transcripts if there were unpaid charges. I also found that they supposedly boot you after 3 tickets. Tickets are $100 minimum and go up by $50 for every unpaid 30 days. As someone who never took and classes from them they didn't have much leverage over me. I just pulled my front plate, got a few spare plates from the junkyard and slapped one over my real plate when I got home for the night making sure no one plate had more than three tickets. For ~$3 day it was well worth the hassle. They're still sending me notices every two months about my unpaid fine for the one time they ticketed me with my real plate.

Seriously, the easiest way to abuse (private) parking systems is usually to make them write the ticket to a plate that doesn't come back to you.

Another "hack" was that the parking gates at most public garages in the DC area had a rubber sweep on the bottom and were tall enough that most 90s compacts could squeeze under if you retract the antenna, saves about $6 per usage.