Just as a data point for this thread; My buddy was chasing battery drain gremlins on his E46, which he rarely drove. He said he always left it unlocked (lives in a safe neighborhood) and for the longest time couldn't figure out what was draining it. He locked it by accident recently, came back a week later and the battery was fine. Seems like when it isn't locked it draws power because it doesn't go into 'sleep mode.'