I attend two different colleges on two different campuses. Three if you count a course I had to take at a technical college last semester.
One campus is very nice (Coastal Carolina). Lots of police, concrete walls with solid, locking doors that open out, not in. Very tactically sound building.
The other college on the campus is not as nice. It's much more expensive, but there are window around every classroom to see (or shoot) through, and the flimsy door opens in.
However, my classmates and instructors in that campus include investigators, an air marshall, SLED (state law enforcement)agents, a county sheriff, some deputies, city cops, an assistant chief, a county coroner, and DOJ people. Not to mention the plethora of military and ex-military, correctional officers, and private security personnel.
Most carry. Oddly, the ones that I figure should (women, Sheriff, asst. chief, other older guys) don't. It's the young guys that carry.