I agree that a bag full of books would probably stop a bullet. Either way, that's a hefty price for such a bag if you weigh risk vs. cost, although it is more affordable that I would have thought.

From the article:
The fathers researched school shootings from 1900 to this year.

I'd like to see the data they came up with. What are the odds of your child getting shot at school?

Although certainly tragic, I think school shootings overall are quite rare, and children are relatively safe. I cant find any stats, but I would bet sports kills more children at school than bullets.

Here are some stats I found on school shootings. http://youthviolence.edschool.virginia.edu/violence-in-schools/school-shootings.html