It is legal, but it also did get banned at my primary school. It continued to be played.
“What exactly are you so happy about?' Harry asked her.'Oh Harry, don't you see?' Hermione breathed. 'If she could have done one thing to make absolutely sure that every single person in this school will read your interview, it was banning it!”
The ban is generally lifted or just not enforced at all after a year or two.
For starters the playground monitors have more important stuff to do than remember the list of banned activities and try to enforce them.