Colleges in the US are now petitioning to allow guns on campus, they might already be. And if he has a carry permit, then having it in public is perfectly legal. And, an unloaded gun seems pretty safe to me.
Yup, if he has a permit for open carry, it'd be legal, as long as the weapon is holstered. That will still get the cops called on him. Most places, if a neighbor/bystander sees an un-uniformed person with a gun, even holstered, they call the cops. Then the cops get to check the permit. It's why most people apply for concealed carry. Also, if we're getting into nitty-gritty, then the gun should be (unloaded!) in a gun safe when not being transported or taken to the range.
Friends who live outside the US: NO ONE bandies guns about like this >.<! Cole's ass would be twelve kinds of expelled for having a firearm in his dorm room and if he'd taken it out in public he'd have had the cops called on him. Lord have mercy, I don't know who taught that boy his gun safety either T_T...
Otherwise, great comic. I thought it was super funny :D.