I was on a volunteer committee for safety and security at Wenatchee Valley High School when Columbine happened. One of the main reasons I moved my family, with kids in late elementary and early junior high, to Leavenworth was to be in a smaller school, where at least the teachers knew everyone who was supposed to be on campus.
It has been years since my kids graduated from Leavenworth High School and it just so happens that Fri morning, I found a band notebook outside beside a tree in my street where kids stop to smoke before school. I took the notebook, and walked right into the school and right into the band room to deliver the notebook at about 8:30 a.m.
Imagine for a moment you are a kindergarten teacher and responding quickly to the sound of gunshots in the hall, you lock yourself and your 25 students in your classroom and take great comfort in the fact that your school is proudly a "gun free zone". One Connecticut teacher faced such a problem and could only bravely put her body in front of the shooter once he was inside the classroom. As a result,she is dead, but some students had precious seconds to escape.
If she had been armed and trained in how to use a gun, she and many more of her kids could still be alive. http://politicaloutcast.com/2012/12/the-solution-to-our-nations-gun-problem/
The big issue here really is a moral problem. I used guns safely, without parental supervision, in the 4th grade. We were taught responsibility and we were responsible.
If parents allow the societal norm to invade their home they cannot expect to get anything better than the worst of societal behavior from their children. Just 10 years ago, my family was rare in Leavenworth in limiting the programs watched on TV, Movies attended and violent "M" for Mature, rated video games viewed thousands of times by the typical junior high and high schoolers in Leavenworth. Perhaps this is time as a parent to take responsibility for your children's "inputs" if you want to receive a different output. But because every parent will not take that kind of responsibility, every school is at risk.
The only protection is to arm and train the teachers. By the time law enforcement, especially in Leavenworth, were to arrive it would be too late.
With the fire dept just across the street, perhaps some of those reliable people would be willing to be armed as well.