To start, the reason schools have this right is to keep its students safe. Schools prohibit weapons like knives, guns, and other objects to make sure no one gets hurt or even killed. Also, the school doesn't allow drugs because the effects may cause harm to the person taking it or maybe someone around the person that took it. Drugs and guns are dangerous; therefore, the school has the right to regulate them.
As another statement, schools have this right to maintain order. Schools don’t