By the way, I work with high school students.
The problem is that parents have sued when the schools suspend their little darling. Their attitude is, the kid's gauranteed a free education, so educate away, as long as you don't inconvenience me by putting the responsibility for my spoiled brat back on ME.
I would have put on the bowling shirt rather than have the principle call my mother in to the school. My mom wouldn't have brought me a T-shirt, she would have brought repercussions...