Having been caught without ID while working at a university site as a contractor, I'm 100% certain that a university somewhere has carted some poor sod off to university prison. They are like extra powerful mall cops.
This is important because many students today are fearful of other people even when on campus transit with a driver, so you better have a verifiable reason why you should be there.
2) University cops in the US are usually real cops - armed and authorized to arrest or shoot you - not "mall cops."