] The UK-based vehicle licence plate manufacturer, Hills
] Numberplates Ltd, has chosen long-range RFID tags and
] readers from Identec Solutions to be embedded in licence
] plates that will automatically and reliably identify
] vehicles in the UK.

More on the license plate tip.

The reference to encryption is interesting. Some digging revealed that these tags have a battery. My assumption was that they are simply choosing codes from a sufficiently large data space such that they are hard to guess, but it looks like I might be wrong. An encryption system could be used such that the tag never provides the same number twice. This would eliminate identity theft by scanning, and it would require that anyone who wanted to use the codes for anything else (parking garage access, toll paying, etc...) would need to subscribe to a network service that would decrypt the tags (thus generating revenue, and a choke point, for the government).

It would be much easier to implement such a system in a license plate then in a drivers license. You can put tags in drivers licenses, but they'll be static, and much easier to steal/fake.

There is a lot of convenience to be had from this technology. There are also "minor" hassles such as getting a warrant check run everytime you drive your car. If they want to find a car in the United States they'll be able to pull up a big screen and see it located. You won't be able to hide. If you steal a car it will get tracked fairly quickley. And good luck borrowing one from a friend. PIs can currently track relationships between people. They'll be watching all your friends cars too...

I think it might be interesting to get an RFID reader and start playing around with the tags in tires. For example you could set up a scanner in your neighborhood and start collecting tag numbers that frequently drive up and down your street. If you get a new one either someone got a new set of tires or someone new is in your neighborhood. I wonder if you can tell anything about the manufacturing date of a tire from its RFID tag? Does anyone know where to get a cheap linux capable RFID scanner?