His Hair
A friend of mine was suspended until he took his cornrows out. They claimed that it was distracting and “ethnically inappropriate.” My friend was adopted and did not know his ethnicity (he is noticeably not 100% white, not that it should matter). This was a predominately white school in the Midwest back in ’02.
Another friend of mine found that the dress code was not gendered specific, so he wore a dress to school. He was suspended for the rest of the day, and they changed the dress code right away.