It's true. I was targeted this way in middle school. I didn't go to private school or anything, but I grew up in a very affluent area where kids were discouraged from showing any kind of edgy self-expression in their wardrobe.
The irony was, I was actually pretty well-dressed, because although I was an angsty teen dying to be edgy, my mom wouldn't let me be seen haunting the halls like a hot topic reject with ratty torn clothes and safety pins hanging about. My parents kind of bought me more couture, avant-grade stuff. I was weird, but not unpleasant or trashy and my hair was always professionally done and my makeup was from the department store while other kids in the social group I longed for were painting their eyelids with sharpie and rubbing wet n wild lipstick into their cheeks.
Anyway, this really pissed off the admin of my grade. She let the trashy "alt" kids fly under the radar despite their midriffs hanging out and their cleavage down to the belly-button, but the second she saw me walking through the front door with tailored pants, loafers and a Swarovski crystal tie on my shirt it was fucking war. I was like 13 years old! First she said the tie was distracting because I'm a girl. Hello, it's a fucking decoration on my shirt give me a break. Then she tried to say the cap sleeves were too loose and that if I moved a certain wY someone could see into the side of my shirt.
I got written up for offenses like these seven times in two weeks. It wasn't because I was a bad kid, either. I got fantastic grades, I was on the school newspaper and showed leadership in the choir and drama programs. It was just someone getting attention for being different and it pissed her off. Once she set her sights on me, coming to school every day was a source of great anxiety. I knew I would be going to the office as soon as I walked in, even though I was well within standards.
I got kicked out of our school dance too btw - for bringing a female date
But this was in middle school so it may be a bit different? I don't know!