If you look at history of mass shootings, even outside of the US, most of them take place in gun free zones. Its not just schools but workplaces, concert venues, nightclubs, etc. I refer to them as cowards because they are. There were police there in 5 minutes but if there was a possibilty someone would return fire immediately it would stop some of these people. Its would be better to have armed security personnel than arming teachers.