Bullet proofing your children

It is an insert that will stop a 9mm round from a glock that is an insert that fits inside a childs backpack. It is an insert the size of a backpack and could be taken out and held over a child's internal organs or head during an attack with a 9mm pistol or under in power or it could stop a bullet if the child was shot through his or her pack from behind. This was mentioned on CNN News on TV today. However, the insert shown will not stop an assault rifle round because most of these would go all the way through a car engine without stopping. On a battlefield a single bullet round can go through 5 soldiers or more and are designed to do this.

How do I feel about this? I think unfortunately it might be a good idea in the present world we live in if your children are in public school or have to walk through dangerous neighborhoods on the way  to or from school