How do colleges know if you're doing multiple degrees at the same time ?

[alzee]

Public colleges are subsidized and some don't wish to waste resources on people earning second, third, ... degrees.

This doesn't make sense. It does not cost them any more to grant a degree than to deny it, unless the graduation fee is significantly less than the actual cost of graduation, which I find impossible to believe. It's probably some misguided attempt at equal opportunity, as in they likely don't want people seeking their 2nd, 3rd or 23rd degree filling classes and making it impossible for those seeking their 1st to enroll.