OK, the school I went too did have a dress code. It was mostly stated that students couldn't wear any clothing that showed underwear(boxers, panties, bras etc), the belly button. There had to be sleeves on the shirt, or an undershirt under the tank top. health issue for the cafe. Shorts couldn't be short shorts, they had to be soo many inches down from the hip, again, if they where to high, then your underwear can be seen. The thin strap shirts that gals like to wear where a no no, again, bra was shown in those.
It was kinda funny, cause 1 spring, our school had to make sure everyone knew those rules, cause the VP was wearing a shirt like that for school.
Now, when my daughter, even goes for my 2 boys, get to that age, They going to know that they not going to show off what they have, or don't have, to get a little edge. It more the respect to others then anything else.