I've had to deal with it a few times, but the cases I had were actually a bit amusing.
First story. Hubby and I (well, then he was DF...it was about 4 days before the wedding) were driving late at night and stopped at a fast food place for a snack. Hubby pulls into the only open parking space (handicapped), hangs his temporary tag from the mirror (just came off crutches, major ankle sprain), and gets out, walks over to the trashcan and throws away a brown glass bottle. And says "good evening" to the police officer standing next to the trashcan
The officer understandibly wants to double check DH's liscense/ID and match it to the name on the permit, and examines the glass bottle (IBC root beer!)
We had a GREAT laugh about this, on multiple occasions later.
Second story. DH and I pulled into a parking spot (handicapped) at our local movie theatre. DH hangs my temporary tag (back injury) and we get out of the car. An elderly couple walks past and the man starts grumping to his wife "they don't LOOK handicapped." She glances at our car and sees the tag hanging from the mirror and shuts him down with "well, they ARE" as they finish walking away.
Not as funny, but it was nice to see his companion shut him down before he started making a stink to us...I probably would've started to cry, I was on so many medications at the time.