I am the say way. And I feel that my heavy use of Gmail and Google Reader meant that I was more likely to use other Google products when needed, ie Docs, Calendar. Without Reader, I don't feel like a Google user, just a Gmail user.
It is probably related to the students sense of choice. A teenager chooses to carry around a smartphone because it adds some benefit to their life that outweighs the cost of being tracked. Whereas with the RFID card, the student sees little to no benefit but incurs the cost of being "tracked".