Comment Re:Allow me to be the one saying "well, DUH!" (Score 1) 165
"And you're transmitting your key to your car"
"Yeah!"
"Aaaaand... constantly while you're walking around."
"Uh.... well,
"Whew. Glad mine doesn't inform anyone and everyone what key I use wherever I go. Someone bad might listen..."
Active keys transmit only when you press the button. Passive keys transmit only when a challenge is transmitted to them. That's why the latter only functions if you're fairly close to the vehicle.
So it is not constantly transmitting the key while you're walking around. It's transmitting the key to anything that can sufficiently imitate the key-request transmission of a car.
Most of these systems implement appropriate rolling-key or challenge-response protocols so that the transmissions are not easily replayable. There are certainly dysfunctional implementations, but most hacks against remote-entry systems attack weaker parts of the overall system than key transmission.
Of course, if you want to duplicate a physical key, all you need to do is get a high-resolution picture when the victim takes their keys out of their pocket.