My keyless remote has the key to the car integrated into it. There is a button that flips the key out when you want to use it. (it's just like the modern VW keys) If any window or the sunroof is open when locking you can close them by holding the lock/unlock button down on the remote. When you unlock you can open the trunk by holding down the button for 2 seconds.

I'm suprised you were able to unlock your car with a replacement and no programing. Since the car uses IR for the remote unlock system I did an experiment. With a Palm Pilot/Visor/etc. You can run a universal IR remote program and capture your cars remote data. You can then use the Palm to unlock the car once. It won't relock it. So the car must send a new code to the remote each time it does a lock/unlock cycle.

The only time I could think of that this would be a security problem is when Valeting the car. A Valet working with a friend could copy the unlock code to a palm and then place the real key in the valet booth. Of course allowing the friend with the Palm to unlock and steal or take the car without a link to the Valet. I guess he/she could just leave it unlocked anyway without the Palm.

I have had my remote stop working for a period of time.... I changed the battery and checked that it was emitting IR with a black and white security cameraand it was fine. So my guess was that it just got out of sync or that the IR reciever in the car has a loose wire. It has been working for over a year now without any problems.

My car also came with a master spare that is real small and fits in your wallet made of metal.