a-HA! Someone else had mail carriers who leave up the red flags.
This is a ludicrous rule. The mailboxes they have in stores are inconvenient and too damned small. Packasges are invariably wedged halfway in. Our mailbox is large enough to comfortably hold both mail and packages.
How bizarre. When I was growing up, I was taught that the flag was used to indicate to the postman that there was something to pick up, not that the mailman had been and gone. Maybe that was just a function of growing up in a very rural area, with a mile or more between houses; if the mailman didn’t have anything for us, and the flag wasn’t up, he could cruise on by. And he always put the flag down when he picked up our outgoing mail.
In my dad’s case, you are talking about two completely different “flags”.
Yes, the red stick-type flag that’s permanently mounted on the mailbox is the signal for the mail carrier to come pick up your mail.
What Dad had was an additional flag attached to a spring. When the mail carrier opened the mailbox door, the spring was released and a separate flag popped up. It’s a passive device. The mail carrier doesn’t have to “do” anything except open the mailbox to insert the mail.