LOL. That really was what it was called..back then.
I had never heard that expression before....probably because there was no such ban at my high school....it was a huge, big-city school and they couldn't (or wouldn't) maintain discipline at even the most basic levels. It was generally a waste of time for me as a result of the teachers' inability to maintain even a modicum of discipline and I was glad when I graduated, so that I could get back to educating myself :-)