When I was in school decades ago, the consequences were that the teacher would single you out and scold you to “follow directions”, maybe they’d do whatever write up for not following directions. I’m sure in some places kids got detention or letters sent home to their parents, etc.

Also the US did not get rid of corporal punishment entirely, the south still has it in some places. https://en.wikipedia.org/wiki/School_corporal_punishment_in_...

Sometimes it's not even direct consequences. You stand out as "that kid" and suddenly, you aren't given the benefit of the doubt the next time there is some kind of conflict at school. Or you are held to the rules -just a bit- more strictly than everyone else. Or, if your grade is on the border between a B+ and A-, they'll give you the B where they give the more obedient kids the A. When you become "that kid" the consequences can be almost invisible and insidious.

At least in the US, teachers and administrators are given rather broad latitude to treat students differently, without requiring justification and very often based on their own personal biases and prejudices.