My company employs several guys that would probably be considered the best locksmiths/service techs in the country - I've verified with several of them that this is a virtual impossibility. There is no such thing as a master key for any auto manufacturer. That's not to say that there aren't other vehicles out there that share the key number (cut pattern), but the chances are slim that a thief will walk up and try his key in your lock and strike gold.
You can, however, obtain a key code using your vehicles VIN code through an authorized service department (at a dealership - not sure about independent shops), but this requires proof of ownership. If someone at the parts counter were to make a key for someone other than the owner of a vehicle using this method, the guy standing behind the counter is legally responsible. Knowing this, they take the responsibility VERY seriously.
Yes, you can order a key BLANK, but this won't open the door to your rig or start a Harley until it's cut.
Vehicle key cylinders are typically more complex than anything you'll find in your home's key cylinders (cam vs pin & spring), and are therefor more difficult to "fool" with a loosely made duplicate. If the news story is valid, I'd say it was just a 1/1,000,000 chance that the keys started both vehicles. I'm sure upon further inspection, the authorities would find there's something else at play here.
