It would be much cheaper and safer to just hire armed security and harden the schools!!
"Scared parents are buying bulletproof backpacks for their children, following the Uvalde, Texas, school shooting massacre, according to manufacturers and reports.
While some of the backpacks can cost as much as $400, and detractors say they can only cover a small portion of a child's or an adult's body, manufacturers report that sales have multiplied as much as eight-fold, the New York Post reports."

https://www.newsmax.com/financ....e/streettalk/bulletp