Fortunately UW has those ancient files from my era stored offsite and not computerized so our SSN plus a digit student ID’s are difficult to access. Computerized grade lists were posted alphabetically (?) by ID number. We had a friend from NJ whose ID did not start with the usual SSN digits we Wisconsinites had- easy to figure out his grade! The reason I know my SSN by heart is all those times I needed my student ID number decades ago.
btw- went on a trip several years ago where several days were spent with a group. UW-Madison has had an entire computer science building since the 1960’s. It is still there- the insides renovated over time as rooms were no longer needed those huge mainframes. I spoke with someone who could not major in CS in the early 1970’s because her MA flagship did not offer the major. She was a math major with CS courses as I recall.