While allowing CCW on campus does not guarantee that it will stop a mass shooting, if it is well known that your inteded victims might be armed it would make you think twice.
If it is well known that the intended victims are armed, then their CCWs were outed by the local newspaper and they would all be enraged by the invasion of privacy. Still when newspapers do that, local crime doesn't drop.
So on a college campus of 19000 students and roughly 2000 full and part time employees (WKU), you have to figure at least half the population is below the age of 21. That leaves 10,500 over the age of 21. Assuming as many as 5% (estimate) of the 21 and over population has CCDWs in Kentucky and they could carry on campus, that would mean there could be as many as 525 folks on campus with CCDWs. Of course, you have to figure that at any given time, maybe only 70% of people with CCDWs are actually carrying on their person (a generous estimate). So that means 368 people. At any given time on campus, there is no more than about 70% of the total population present, leaving 258 potential CCDW people carrying guns. WKU is a 200 acre campus, so that gives you about 1.29 CCDWs per acre averaged. Of course, you will have a tremendous amount of concentration of CCDWs where people congregate. You could divide those 258 people by the 65 buildings present and get an average of nearly 4 CCDW people per building. So people congregate in the open areas as well, so let's compromise that there might be 2-3 CCDWs in any major occupied area of the campus.
Of those 2-3 CCDWs in the area, how many are in a geographic position to be able to respond? If you don't have line of sight to the event, response will be difficult.
To add further confusion to the problem, assuming that the 2-3 CCDW folks who might be in the area of a given event, just how many are going to respond to a crisis if they are not themselves immediately under attack? We know it isn't the cops job to protect individuals and we can't count on them. Can we could on CCDW folks? How well trained are they?
Sorry, but this notion that bad guys are fearful of concealed carry folks as a deterrent to crime is really pretty silly. There just are not enough concealed carry folks yet to make a real difference on such a scale so as to scare bad guys into not acting.
Charles Whitman, as effective as he was, would have killed a hell of a lot more people had the citizens of Austin not returned fire and pinned him down.
Charles Whitman wasn't pinned down by the armed citizens of Austin. He researched and picked the clocktower building's observation deck as a high ground and well protected shooting hide. It was where he was going to make his stand from there. He wasn't mobile at all and he wasn't going anywhere. Hell, he brought a footlocker, food, water, a radio, gun cleaning supplies, etc. He wasn't ever coming down from up there, not alive.
Shooting back by the citizens of Austin may have kept Whitman from being able to freely pick and choose his shots, but he was not pinned down. When he came under fire, he simply moved to shooting from the drain holes.