Several years ago, while making a trip to the Catskill area, I stopped near the large shul in Woodbridge, NY (I forgot its name). The rabbi has a reserved parking spot across the street from the shul.
The sign in front of the spot says:
"Reserved for the rabbi. Violators will have to deliver the sermon on Shabbat."
I must admit, it is a memorable humorous sign. I love it. But, I'm curious. Could the rabbi halachically impose his own made up "penalty"?
Offhand, I think he was being funny, but, let's say he really wanted to teach the violator a lesson that he shouldn't park there again. Is the rav allowed to impose any penalty he wishes for the purposes of "teaching a lesson"?