I know for a fact that the E36s (and up I do believe) have this feature. The keys have a chip in them that sends a signal to the car saying "hey, I'm a legit key, it's cool to start the car." The spare key, master key, and plastic "wallet" key all do the same thing. This is the reason these keys can ONLY be replace by the dealership for quite a substantial fee.
Originally Posted by johnnybayonne
I eat, sleep, & breathe BMW