I found this thread interesting, so decided to look at my keys and owner's manual.
In the manual I came across this:
One copy of the red service key is supplied with your car, and it only locks/unlocks the doors and starts the engine. This key can be used when you hand over your keys to strangers, since the glove compartment, the rear object compartment and the luggage compartment cannot be opened (this can be done with the main key)
What is the rear object compartment? There is a cubbyhole at the rear of the centre console, but it does not have a lid.