Maybe it's against the law in your state, guys, but not mine. Almost everyone in the NJROTC was wearing a Marine BDU with EGA and all, including caps. But, we had leighway. Our Naval Instructor is an ex-Marine First Sargeant. And last week we had "Superhero" day and he said "I'm surprised no one dressed like me!" Well, this week to toss on to the joke, all of us wore BDU costumes and stuff. It was pretty funny.
I find it disrespectful when it is blatant disregard of what the uniform means. Being in ROTC almost makes it feasible. If you're in ROTC and have a "Mini-Boot Camp" ribbon, you have a pretty good reason to wear a BDU. You should ask them to recite a single Order of the Sentry or something like that. If they can't, they don't deserve it. Simple as that.
I also find it okay when little kids wear it. It's cute. If you're voer 14 and wearing it, UH-UH!