+1If they want to protect their students from those inclined to violence they'd be wise to.
"The laws that forbid the carrying of arms are laws of such a nature. They disarm only those who are neither inclined nor determined to commit crimes…. Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than to prevent homicides, for an unarmed man may be attacked with greater confidence than an armed man."
- Thomas Jefferson, Commonplace Book (quoting 18th century criminologist Cesare Beccaria), 1774-1776
"That no man should scruple, or hesitate a moment, to use arms in defence of so valuable a blessing, on which all the good and evil of life depends, is clearly my opinion."
-George Washington, letter to George Mason April 5th 1769