In some cases a utility bill or an easily forged document was enough to do the trick.

CENTERFORSECURITYPOLICY: The Case for a Secure Driver��s License

The sophisticated operation used "forged document specialists, " a locksmith and a portable computer to sync a key to the vehicle's unique code, allowing the vehicle to be stolen without damage, authorities said.

CNN: Custom-order vehicle theft ring busted

And placing trust in a single document, some say, will actually make life easier for criminals - because only one document needs to be forged.

BBC: Probe exposes fraudulent ID trade