I always lock the van before going to bed using the button on the driver's door. Opening the slider from inside doesn't unlock the other doors / tailgate though, which I always forget, and then have to clamber back in to unlock the tailgate from the drivers' door button.
Having consulted the manual, I'm actually none the wiser: I think using this method to lock the van disables the anti-theft alarm. Interior motion sensors obviously are not active either (I think we'd know!) But what about locking the van using the key fob? I've been pressing it once, then pressing again and holding to fold the mirrors. I thought this was "double locking" or something. Since reading the other thread where this is discussed (Ferry to Spain thread I think) I've realised one press and hold folds the mirrors and locks the van. What happens when I press a second time then? It sounds like some more locking going on, but am I actually unlocking the dead bolts (or whatever they are)?