Obviously the adults could have restrained her without handcuffs. That would have involved holding her physically for an extended period. Parents would then claim sexual assault.
Good point.
Another poster said that the school systems are phasing out the "rubber rooms" where the really unruly kids get tossed until they calm down. (I remember one in my school. It didn't get much use, as I recall)
Sez Me, when the best and safest punishments are taken away, cops and handcuffs start looking like a viable alternative. Especially if the school admins are dim bulbs anyway and don't have much to work with, to begin with.