I was in middle school when the Columbine shooting happened. The following year, they updated the dress code to require everyone to tuck in their shirts with the stated reasoning that it would prevent people from concealing weapons.
I was in high school. Trenchcoats were pretty popular to wear at the time with the nerds and geeks. We even had the kids in choir who looked up to an a capella group called "The Trenchcoats", who would regularly wear them.
Trenchcoats got banned because of Columbine and the choir kids werent allowed to wear them anymore. Even the a capella group changed their name to "The Coats" around that time. Weird times, man.