Corporal punishment is used only on the worst kids. A little swat is good for some kids. Corporal punishment hurts all kids, victims and witnesses alike. It increases learning problems and decreases student's ability to concentrate and remember. In severe cases, students subjected to corporal punishment exhibit symptoms of post traumatic stress disorder, similar to the syndrome experienced by Vietnam veterans.
Corporal punishment prevents unruliness.
It's okay to use corporal punishment if parents give permission. A spanking at school is very destructive to a child's sense of self-worth. It hurts other children too by frightening them or sending them the message that violence is a solution to problems. Also, paddling at school sends the message it's okay to hit kids at home, too. Using corporal punishment lets kids know who's in charge.