Wax the windshield. They'll learn real quick.
Long time ago we lived where we had one space and the rest was street parking in front of the house.
This dickwad that lived 2 blocks away owned a cab company and would park his cars in front of our house and leave them for 3 days at a time.
They were always freshly washed - until I would go out and water the parkway that had a convenient strip of dirt on the curb side, made sure the pressure was maxed.
Completely mudded out, rims and all.
He eventually got the message and moved them 3-4 spaces forward in front of someone else's house.
Windshield waxing is a good one though.
Maybe shove a stick into the valve stems.