[ktrgardiner]

I'm not sure about Brown, but at my school we had student IDs which could also act as credit cards for "school money". Meal plans would come with a set amount of school money and you could load more on the card. This money could then be used at places around campus as well as local restaurants and grocery stores that would accept the card. Certain services (such as delivery.com which was popular in the area) also accepted school cards. So my guess is that the student IDs were simply the number associated with the credit card for using special school money.