He's probably talking about the flashing red LED by the door lock.
Your other Passat has this light, but it doesn't start blinking when you lock the doors? This could be either a bad LED (arm the system, pop the trunk, and see if the alarm goes off) or the alarm is disabled. Sometimes you can re-enable it using a VAG-COM.
When you lock the doors, does it 'beep' at you at all?