Metal Detector Knife

Would you let your child go to a school that felt the need for a metal detector at the entrance?
I do not quite get this – if a detector metal is needed (to keep knives in a school) why would someone that their children attend school at all? I would not let my children in an environment full of psychopaths – even if psychopaths have been temporarily disarmed.
You would have to tutor at home then, cos you do not always get say in which school your child goes to. Besides he would prefer if it meant some psycho did not have a knife.
Metal Detecting. Kid with a knife.