A well trained carrier will pick up the mail when the flag is up and also close the door, Supervisor should be given a service talk to this bad manner mailman...
The only person that can really answer those questions is your carrier. I would complain at the office if speaking to the carrier doesn't work. We might have the same carrier- I ended up getting a locked box for the open box issue and when I have outgoing mail I drop it in the box at the post office.
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