While a bullet-proof backpack sounds like good protection, it is just feeding into the emotional turmoil of fearful parents. The odds of a child having the backpack handy, and then being able to use it against an active shooter are very tiny. It would be better to have more protective measures in schools, like security doors on the classrooms, or armed guards on the grounds. These cowards who shoot at unarmed people will not want to attack a defended or hardened location. Besides, very rarely do the shooters have legal weapons, which means they could also have stronger ammo, which will blow through this 'bullet-proof' material like it was water.