Sure, the principal can do ban whatever she wants from classrooms, within reason of course. If they found the fidget spinners to be a distraction form learning, they kind of have to make that decision.
Personally, we’ve found that all fidgets are more of a distraction in the classroom for my son, so less than helpful.
Penny
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism