First, don't be a self-hating American. It is really annoying. Now...
As far as I know, the only clothes my students own are their school uniforms and I see them in those 24/7. I am talking about the track suits. Only high school kids wear the dress uniforms all the time.
What is really funny, is when you see a kid come into elementary school with a shirt that has a big marijuana leaf on the back while carry a pencil bag covered in Playboy bunnies. Yeah Chigusa-sensei, that's a nice "maple leaf" and what cute little bunnies.