Cautionary tale for Ozbargainers! My partner and I were away in a different town over Easter. We approached my Subaru Outback 2004-ish on Saturday evening and I unlocked it via the central locking button on the key, but my partner had already opened the passenger door before I pushed the button. I didn't think too much of it apart from making a mental note to check it out.
Next morning, we found that the car ashtrays had all been pulled out, glovebox was open….someone had gone through the car while it was parked in front of our Air BnB. The only thing missing was some wine we had bought on special the night before. Fortunately, there were no other readily negotiable items or cash in the car.
So - the front passenger door has a central locking fault but the key buttons continue to work as usual. Can't say how long it has been like that. The door is now manually locked until I figure out if it is worth having it fixed (or if I can fix it myself).
Moral of the story - don't always assume that the central locking locks every door on your car! Before this incident I had no reason to doubt that it did. I'm wiser now.
My second (spare) key requires me to push "lock" twice to lock all doors (and vice versa to open them). First click only affects driver's door. Check your other key, or try pressing your existing key twice.