One thing it would be useful to keep in mind about rape on college campus is that a lot of time it is done by someone the victim knows, whether a boyfriend, friend or a casual acquaintance. I'm not saying students should not be allowed to carry, but a gun does little good if someone slips a roofie into a student's drink at a party, or gets them inebriated to the point where they cannot resist.
Then again, neither do whistles, safe zones, and call boxes.
To really address the issue of sexual violence on campus, we would need to have an open and frank discussion about what drives it and how to prevent it, but that would involve universities admitting the problem comes from their own student body (can you say bad for recruitment?) and taking the time and effort to find a meaningful solution. One that would have to involve changing how men view women, for starters.
Of course, it's easier to ban guns and tell students to wet themselves.