"In a future world laced with RFID spychips, cards in your wallet could
'squeal' on you as you enter malls, retail outlets, and grocery stores,
announcing your presence and value to businesses. Reader devices hidden
in the doors, walls, displays, and floors could frisk the RFID chips in
your clothes and other items on your person to determine your age, sex,
and preferences."
Here is a link if you want to read more:
http://www.strike-the-root.com/52/lfb/lfb1.html
