Picture the scene. The Parent is outside The Boy’s bedroom door…

The Parent: <knocks on door>
…..
The Parent: <knocks again, a little louder this time>
…..
The Parent: <tries one more time>
…..
The Parent walks to the sitting room, grabs their mobile phone, opens the phone app and scrolls down to The Boy’s number, hitting dial as they walk back down to the bedroom door.

The Parent waits for the boy to answer

The Boy: Hello?
The Parent: I knocked, but you didn’t answer
The Boy: Oh, sorry. My headphones are on. I didn’t hear you.
The Parent: OK, well, it’s dinner time.
The Boy: OK, be there in a sec.

The Parent hangs up the phone and returns to the almost ready dinner.

We have a house rule… closed doors are fine, locked doors are not. Closed doors = privacy, without seclusion, and that privacy must be respected BY EVERYONE. So I knock, and wait for an answer. When I don’t get an answer I try all other means, before opening the closed door.

I trust that he is not hiding anything (no locked door)
He trusts that I won’t just walk in (knocking before entering)