I first went to college from 1984-1988; we were required to show our student ID to get into the library, as well as to check books out.
We also had to show them to get into the cafeteria, as it was our meal ticket; people without an ID card could not enter, because there was no cashier in the dorm cafeteria - even if you were known by the person checking - it had to do with the accounting system, which was primitive enough at the time that they couldn't input data manually, only by inserting the mag stripe on the ID.