Back in 2005, I was at Rochester Institute of Technology, and our ID cards encoded our student ID... which was also our social security number. The Student Government made you take attendence by student ID number for certain functions, so at one point as officer of one of the campus's major clubs I was sitting with a spreadsheet of the names and socials of >1000 students.
They were also low-cap magstripes, and the checksums were predictable. Inventive students had a database of a few all-access keycards that were used to sneak into the tunnels under the academic buildings at all hours of the night...
When I was in college, 91-95, your SS# was your identifier. It was the unique code that everyone used when they needed a way to identify people.
I gotta dig it out, but I think my SS# was printed right on my school ID (and the state issued card allowing me to buy alcohol with my out of state driver's license -- Vermont).
My university (UT Dallas) once hosted a talk about privacy and security, during which they emphasized that it was important to keep your social security number as secret as possible.
Then they passed out sign-in sheets and asked us to sign in with our student IDs - which were our social security numbers.
The sign-in sheet made it through approximately half the room before someone pointed out what was happening. The organizers looked completely baffled.
They were also low-cap magstripes, and the checksums were predictable. Inventive students had a database of a few all-access keycards that were used to sneak into the tunnels under the academic buildings at all hours of the night...