Three or four years ago while visiting schools in Kemmerer, I rang the doorbell at an elementary school and was buzzed in. I explained that I was surprised the door was locked before she explained the school's reasons.
At that point, in playing the devil's advocate, I asked what was to keep me from committing mayhem. Our conversation ended on a friendly note, of course, as she stated the locked door was a nuisance.
We visit schools coast to coast, and most are without locks, while some have double security. The lady from Vernal could go back 100 years and NOT find a single case where someone attempted to or broke through a front door or any door ... except to burglarize, perhaps. Unlock the doors.
Many schools also lack police on campus. Parkland proved a point. An article in the Harvard Review, April 10, 2015, suggested cops stay away from schools. Uh huh, Maryland. A month ago or so the principal had been warned.