Closed doors pet peeve

I know this is a rather silly pet peeve, but it drives me crazy that S16 feels he has to have his bedroom door closed 100% of the time when he's not in his room. I don't care about the door being closed when he's in there! That makes sense, everyone needs privacy. But every single time he leaves his room, he closes his door behind him. Even if he's just leaving for two minutes to go to the bathroom. And now SS13 and SS12 are starting to do the same thing because they mimic everything he does.

I know that part of why this bothers me is because SS16 is a secretive kid and multiple times has been caught lying about stuff, including hiding things in his room (not super bad things, mostly just electronics when we have a no video games in bedrooms rule). It also can get confusing about if he's in his room or not, and there have been several times where we've been knocking on his door thinking he can't hear us because he has headphones in, only to realize that he was actually in the backyard or something. I honestly wish I could find a way for this to not bother me, but it just really gets under my skin for some reason. Do anybody else's kids insist on keeping their bedroom doors closed, even when they're not in the room?