I was at school in the seventies, but I don’t remember any attempts at humiliating pupils deliberately. If we were late for assembly our names were taken by the teacher allocated to be there, and we were expected to wait in reception until it was finished. If we were late three times or more in a term a letter was sent to our parents, which I thought was fair.
Our form teachers patrolled uniform, it was quite strict. We went to our forms for 10 minutes after assembly. If you transgressed you were spoken to at the end of the form period before you went to your first lesson, but not in front of everybody else - I was one of those who tried it on frequently, nail varnish, coloured socks, skirt rolled up, make up etc., but I never felt picked on because you knew it was coming. We did win a victory on ‘pork pie’ shoes though, which were not regulation uniform - a few of us all wore them at the start of the new term because we hated the regulation shoes - and I still remember the joy when they were deemed acceptable.