Gun free school zones create "victim zones."
We know that in all cases school shooters encountered teachers that acted heroically to protect the children. These teachers should be afforded the same rights they have outside the classroom inside the classroom.
Many teachers are already trained concealed handgun/weapon permit holders but not allowed to bring their self defense implements into the classroom.
Armed teachers may not be able to stop all school shootings but they could mitigate damage.
Criminals do not follow laws... bans and restrictions only impact law abiding citizens.