I once handled a similar situation in a different fashion. Dude (early 20s) and girlfriend parked in the only handicapped spot available. They obviously had just come from the gym and RAN into the vitamin store. When they exited they came to the restaurant next door where I was eating. When they were leaving I made a point of rushing over to hold the door open for the poor invalid, and told him I'd be happy to assist him getting into his Mercedes. They both turned visibly red, and I don't know if it really had any affect, but I like to think the embarrassment will carry forward and prevent them from making the same selfish choice. Made me laugh anyway.