We had to stand up whenever a teacher entered the room. 1998-2004, all boys grammar school. That rule was archaic even then.
I've taught at a fair number of schools in the past decade (as a supply teacher), and at least one school had reintroduced such a rule.
Stuff at school that is irrelevant in a modern workplace:
-School uniform / ties etc
-One occasion a teacher taking it upon himself to do up my tie for me when it wasn't done up properly (without asking first)
-Addressing teachers as "Mr / Mrs / Miss xxxxx". Aside from the unecessary genderisation, what other part of life still does this?
The Mr/Ms aspect, along with Sir/Miss, seems to be a dividing line between schools and colleges/universities. That formality seems to dissolve away once you get to tertiary education. (Though in other parts of the world, all lecturers are given the courtesy title "Professor".)
One area that is idiosyncratic to Welsh-medium education is the use familiar and formal terms for teachers (ti/chi, equivalent to tu/vous in French, or thou/you in older English). It was commonplace and expected in my upbringing, and remains relatively common in Welsh-speaking heartlands, but is less prevalent elsewhere, even in designated Welsh-medium schools. I always referred to other teachers as 'chi' in front of other pupils, but typically 'ti' in the staff room.
To my view, school uniform seems to be going in a cycle. In the 90s, my primary school replaced shirt-and-tie with a polo shirt, but my secondary school remained shirt-and-tie for all years. They later switched to polo shirts for all but the sixth form.
Other schools have recently moved away from the polo shirt, returning to shirt and tie. I theorise that it's to improve perceptions and standards (both internally and externally.) Curiously, two of the rougher schools I taught at (with many from deprived backgrounds) had blazers as part of the school uniform, which made for an interesting contrast.
Another school I taught at held a parent/pupil referendum on changing their uniform while I was there, and there was overwhelming support for a blazer in addition to shirt, tie, and v-neck. Kids grumbling about the blazers after their introduction were reminded of this fact.
Finally, one school planned to introduce a rule that not only shirts and jumpers, but also trousers/skirts must be embroidered with the school logo. Many teachers viewed this as a folly that would increase uniform prices by forcing parents to use authorised suppliers, but one department head viewed it as a masterstroke to get rid of various types of jeggings and jeans that pushed the boundaries of the "black trousers" rule. The presence or absence of a logo would be far simpler to police, with no room for arguments as to whether a given style of trousers broke the rules or not.