Luckily, this is not a thing anymore. At least not in Canada. We're in a small rural town in Alberta, so I have to assume we are in pretty much the worst place in Canada for it, too. But my niece has ADHD and they are very inclusive about it now. Chewing gum is allowed, music is allowed, fidgets are allowed, and wiggly chairs are allowed. And none of the other kids in her class are bothered by it, they have their own things too, and they are all learning just fine.