Adam Lanza chose Sandy Hook for several reasons. Familiarity with the layout and the fact it was a gun-free zone were the top two.
His actual goal was to be the most prolific killer in history [the highest score if you will] Having no one to even slow him down made this an easy task.
All these BS excuses of what 'might' happen (if teachers etc. are armed) only further endangers our children, families and friends.