I recently found this out on my trip to Silverstone last week. Due to the fog I put the lights to on. When I parked up I forgot to turn them off. When I got back to the car and saw the switch was on I got worried my battery would be flat, but the car started, so the lights must have gone off by them self as they weren't actually on when I got back.
Therefore it means you can just leave it in the on position and they will come on when you turn the ignition on and then they will go off when you take out the key from the ignition.
With my highline dash I have set my leaving and coming home lights to 30 secs. That is a great feature. Well worth upgrading for the extra features over midline