As technology progresses so do the capabilities of thiefs.

From Wired:

As part of a talk on the insecurity of wireless devices at the Black Hat security conference later this week, Cesare plans to reveal a technique that could allow anyone to spoof the signal from a wireless key fob and unlock a car with no physical trace, using a codebreaking attack that takes as little as a few minutes to perform. “I can use this to lock, unlock, open the trunk,” says Cesare, an Australian researcher for the security firm Qualys. “It effectively defeats the security of the keyless entry.”