DS2 has been given an after school detention for not having his book in class. Personally I think it's a bit harsh as it's his first offence, but then I'm the one having to re-organise my plans and spend a couple of hours collecting him.
My friends son in Y11 (at a different school) has been given an after school detention for getting an A on a past GCSE paper, when he was expected to get an A*.
What's normal at other schools?