You know what's regular and acceptable for schools? Recess, whiteboards, and dodgeball. Know what else? Lockdowns.
However you approach the issue of gun ownership, why don't we just start by stating the facts:
The one thing that's impossible to deny is the amount of innocent suffering, much of it borne by children, due to gun violence. There are some people who say this reality entails more gun ownership. There are some who say it should mean greatly restricted gun ownership. What's most important is that these people talk to each other. The point made by this poignant PSA is that people who disagree can avoid the issue. But children cannot avoid the issue.