A good one I heard about
A guy I know got clamped, bent down as if examining the clamp. What he actually did was to squirt some superglue into the lock unseen.
He then paid the fine, and of course, the clampers could not remove the clamp.
“look pal, I’ve paid the cash so unless you release my car in the next 2 minutes it is going to cost your firm a lot more than the clamp release fee I have just paid” 