While I realize that this is about safety and not guns, I'd like to point out that the 18 school shootings number is a deceptive statistic put out by the anti-gun Everytown for Gun Safety Support Fund. They include any time a firearm is discharged on school property - including college campuses.
3 were mass shootings - defined as more than 1 person was injured.
9 involved no deaths and no gunshot injuries.
2 were suicides, with no other injuries (including one at a former school that had been shut down 6 months prior).
3 were unintentional (although one caused injuries).
1 involved a robbery in a school parking lot.

Again, I realize that this post is about protecting the children but I believe that putting the school shootings are rampant narrative out there after a tragedy like Parkland does a disservice to the truth.