I remember, I went to school with a girl who went to Japan as an exchange student, in 1990. She went to a town in Hokkaido, and she said in a letter that she sent to our Japanese class that she had random people touching her hair because it was blonde. While I know blonde hair is a novelty in Japan (not so much now, with some dyeing their hair), I would still say, it's not etiquette to touch a person's hair without permission.

I remember, when I was in Year Eleven, a kid put chewing gum in my hair and one of my teachers cut clumps of it out.