Another good one for the partners, has them in hysterics this.
Clever cars know if you've walked away and not locked the car. (BTW this doesn't apply to my Maserati). So if your partner decides to stay in the car while you go and do something, jokingly lock her in, but of course don't forget to unlock it.
A minute later the car will recognise that you didn't open a door and relock the doors for you, activating the alarm in the process.
I'm telling you, when you come back to the car they're hysterical!!!!!