My middle school boys attend a very strict public prep magnet school that requires khaki pants brown shoes and belt and a long or short sleeve white button down oxford cloth shirt. Hair must be above the ears. Girls may wear what the boys wear plus they can wear a black watch plaid skirt three inches below the knee. They enforce the code rigorously.

I would have probably added a tie to the required dress but it is acceptable as is.

Other local public schools have similar codes but enforcement is spotty. My 20 year old daughter rolled up her skirt slightly above her knees in HS and wore rather odd shoe laces

Seriously, I am not a stickler on dress codes but I suppose it is a problem with where to draw the line. Hard to control piercings that are out of sight but I wouldn't favor allowing tongue, nose and other facial piercing in middle or high school.

As for uniforms, they didn't have them when I was a kid and it made it pretty obvious who was poor and who was not. Nowadays, I suppose it is the radical styles as well as the economic factor that has made uniforms common.