Honestly, this is just really idiotic to me.
If they dont have these fidget gizmos, they're just going to use other random objects instead. I used to do this with pens, back in school. The end result was that I'd have ink all over my hands. And if anyone had tried to take the thing away from me, well.... they'd probably have found themselves unable to. Tended to be very, very stubborn, whenever I thought something was bloody stupid, which was always. Like gym class, they always wanted us to play sports, I hated sports (as someone who hated basically everyone else in every class, you bet I wasnt going to try to be on a team with them) and simply refused. I quickly found that many teachers tend to get more than a little lost when that happens. Ended up on a seperate mini-class that often went to the local driving range to hit golf balls instead. Had the odd side effect of me carrying around a golf club all day (never went to my locker). Sure wouldnt get away with THAT these days, would I...
The point though is that they arent ACTUALLY accomplishing anything with this, except irritating the students. Which never helps. The ACTUAL solution would be to make the lessons less freaking boring. Change the system instead of blaming absolutely anything else. Honestly, as always, I see the education system as being a total disaster. It doesnt keep anyone actually interested in learning much, and of course you have bullying with nobody doing anything about it... whole thing is a mess. But no, let's ban these random harmless objects. Ugh.