The mailbox in my building is broken. Nobody can remember it being any other way. The lock is busted so anyone in the building can get access to every apartment’s individual boxes in the same way that the mailman does. It’s not a huge problem since there are only four apartments in the building and the box is behind a locked door to the street.
I saw the mailman come one day to deliver mail. He used a key to unlock a box on the outside of the building from which he retrieved a key to first unlock the outside door and then another to "unlock" the mailbox.
Every day, my mailman unlocks a mailbox that is always unlocked and, in fact, unlockable. As far as I can tell, he’s been doing it for years. I don’t have the heart to tell him the truth.