We have a secured school during class hours. There is only one entrance unlocked during school hours, and that is to allow entrance through one office door and to exit out the other door. When parents and/or students enter, they must check in. Visitors receive and wear a stick-on tag to identify them. Tardy students are dealt with at that time. Our custodian locks the gated entrances to our school as soon as the morning bell rings. He then unlocks the gates right before dismissal. It seems to work well, as we never have strangers walking around campus. Also we have a buddy system, where students never go anywhere alone.