Tbh, idc whether or not authors abide by school dress codes or not (some highschools don’t even have a dress code). I know I’d wear crop tops and jeans ripped above the knees all the time, cause the teachers at my school didn’t really enforce the highschool dress code like that anyway.
I don’t think it matters, and I don’t think authors should get hate for it.
Edit: Same with tattoos. I know quite a few people I went to school with who are littered with tattoos. My best friend tatted a heart on my ankle in the school bathrooms (we were ghetto 
)