Information Security Operations for a tier-1 university here. If the university is public, which most are, they require SSN documentation to report to the state

Information Security Operations for a tier-1 university here. If the university is public, which most are, they require SSN documentation to report to the state as technically your taxes helped pay for that school. This is all tied up in politics and documentation for everything really, but that's just how the politics seem to work. They are also required to file their assessment of your fees and tuition to the IRS via a 1098-T form. Also you are awarded various small hidden grants on your tuition payments if you've a valid SSN as your taxes (or your future taxes) went towards that school's funding.