I do have a high school diploma and this is a tiny bit of what I endured to get it.
Deal was this: infraction of rules or annoying the Dean could result in the issuing of demerits which were prominently posted on the bulletin board in the hallway opposite the office. Accumulation of 20 or more demerits resulted in the loss of "social privileges" and that was a big deal, because social life was severely restricted in the first place and loss of what few privileges there were available meant, well, isolation from any activity other than going to classes. During my junior year the Dean issued me twenty-five demerits for a single and honestly my first infraction in over two years.
The Dean and the school he represented were wrong, too, but how foolish of me to try to re-argue the case seventy years after the fact. Well, he had the strict letter of the law on his side.
However there was an escape clause. By putting in hours of labor on campus each hour would erase one demerit. I worked in the kitchen scrubbing the CEILING with soapy water and scrub brush. Picture the dripping down on my head and the water running down my arms. And thus I worked exactly six hours thereby changing the posting in the hallway to "19 demerits" and there it stood for the balance of the school year.