i do remember that in the early 1970s it was a school rule at my all boys school in England that boys upto the sixth form had to wear a school cap to and from school, in a car, bus, train, on a bycycle or walking. Not doing so and being caught by someone in authority would lead to a punishment of some type. However the ruling was lifted before I made the sixth form so that would have been around 1972 I guess.

For a long time we could wear hats to school, but then a new principal took over and made a rule of it. There was a student walk out over it as it was seen as ignoring other more important school issues at the time. The principal got his way in the end.

It's part of the school uniform here. Except for middle schoolers and up but they really should.

Just a guess but alot of early schools were started by churches and so some of the traditions that stuck around were from church.

I think because some people always spoil a privilege like that. Some T-shirts are really bad and hats could be too.

No hat no play!

Its called respect and courtesy. Something parents arent teaching

Because it’s rude to wear a hat in a home or building

No idea. Unless hats can be used as some kind of gang sing?