I've always thought that students that are incorrigible should be sent to reform schools run by United States Marines on a boot camp model. I've also felt that parents should not have a say in this. If they can't control their children, someone else should have that duty.
I've envisioned that if a school principal decides a student is incorrigible, he/she gets handcuffed, and a military van picks him/her up to take him/her to the boot camp. The parents will be notified after the fact.
It would save many lives not least those of the incorrigible.