I can see it happening in this paranoia-security climate, it would probably be marketted as the next stage in shopping, like Japan currently has with mobile phones. No need to take a wallet or a card, just point your hand at the scanner and it automatically deducts the amount from your bank!
No need for keys! Just touch your hand against your house door/car door/locker door and blam, open it goes!
Little mention that you can be tracked and catalogued by the authorities, just happy little sheep enjoying their circuses.
