Nothing, really.
What bothered me the most is that people never followed them, and no one ever enforced them.
I remember making a scene in one of my freshman classes when I stood up in the back to tuck in my shirt, and people kept giving me disgusted faces. Presumably because I unbuttoned my pants.
I looked around and said
"So it's ok for all of you to walk around with your pants down to your knees, but the moment I tuck in my shirt, everyone loses their shit?"