I've taught on a campus on which about 1/3 of the faculty are packing at one time or another. Never had a worry. In fact, I felt reassured.
Heck, some of my students were probably packing. Never worried a bit.
Now, if you are at at VT in the spring of 2007, as you huddle in your classroom and you listen as Cho moves room to room, pleas for mercy, a burst of gunfire, moans of the wounded, sound getting closer with each room shot up, you're looking into the eyes of your fellow students, would you feel safer knowing one of them had a CCP and was packing? Or less safe?