Guy Kewney turned in this article in eWEEK about RFID and privacy. He's a bit harsh, but makes some interesting points:
"Of course, you only have to say, "RFID," and even quite techno-innocent people will blench, turn pale, and start chanting mantras about privacy. They are afraid of ghosts. They have this fearful vision of a future in which your clothes contain RFID chips and as you walk down the street sensors pick them up and report your location back to Big Brother.
"Reality, naturally, is less exciting. For the few who have got all their information about RFID from strident activists with wide mouths and closed ears, these things only have a range of about three inches. And yet...reality may, after all, turn out to be even more exciting because these mobile payment gizmos look like they're going to betray far more about their owners than you could possibly believe (unless you were working in the field, of course).
"Amalgamate the data from the bank with the data from Exxon with the data from a transit system. Then add a loyalty card system, a mobile phone payment network, and a Government ID card system. The result: the State can track every citizen with far, far more detail than a simple RFID tracker could ever manage.