The I-fobs are all supposed to use "rolling" encoding, so recording them with a garage door style system like Homelink won't do it. As far as I know, even the early ones are still impervious to simply walking up and starting the car. However, there are two separate systems inside the fob (actually 3, if you count the "emergency" inductive system underneath the logo). The short-range system that works the door requests and ignition is GHz band and is bulletproof to my understanding. The button system on the fob is FM in the garage door frequencies, even though it doesn't use garage door coding. Nevertheless, with the early fobs, I personally saw instances where a particular fob would pop the trunk or doors on another car. So the answer is, "Yes and no."