what an unusual use of authority! i don't recall many public humiliation policies from the schools i've gone to. ha, "no swearing" is always one of the first rules instated in certain drinking games, for that very reason. it works even better on the imbibed.
my best friend growing up was catholic; her mother had one of these. i think the charge was one quarter. (now, it makes me think of "ten in the swear jar," a band i only know of through a song they covered.)
and what of minced oaths? "sir, i said 'shish kebabs.'"