School Visitor Verification for Safety

Unfortunately we live in an environment where violence and mass shootings are becoming a regular occurance. Nobody wants our schools to become warzones with metal detectors, armed guards, bars etc. Most schools lock their doors an easy protection mechanism. Unfortunately, they allow entrance simply by "buzzing" the door open when someone rings the doorbell, with the expectation that the person will walk to the office and signin. It is at this point a drivers license might be checked to keep sex offenders out. This seems insufficient and too late. There is a better way ...