Many of us already use RFID tags routinely. Examples include:
Proximity cards, that is, the contactless cards used for building access.
Automated toll-payment transponders – the small plaques mounted in automobile windshields. (These are usually semi-passive.)
The ignition keys of many millions of automobiles, which include RFID tags as a theft-deterrent.
Payment tokens: In the United States, the SpeedPass token for petrol station payments is an example. Contact-less credit-cards, like American Express ExpressPay and the Mastercard PayPass use RFID