Boingboing TV has an interesting video clip showing how easily RFID enabled credit cards cards can be hacked. Pablos Holman, Hacker and Futurist, says:

The credit card industry understands very clearly that creating a secure system isn’t really the priority. Creating a system that feels secure to the user is. In reality it is easier for me to get numbers now than it was before with the old card. All I need to do is get near your ass with my reader.

If credit cards can be hacked this way, I would imagine that the”getting near your ass” technique could be used to hack RFID enhanced driver’s licenses, passports, or library cards.