"Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds" is an informal motto of the US Postal Service. However, mail carriers are not obligated to deliver your mail when you're obviously messing with them.
Vlog Creations, a YouTube channel dedicated to non-harmful pranks, invested in a long series of mailboxes of varying sizes and heights, and gradually installed smaller and smaller ones to see how long it took for the mail carrier to notice. Yeah, he noticed, but he's more amused than annoyed. Then it became a battle of wits to see how small they could make the box and still get their mail picked up and/or delivered. My mail carrier will never pick up outgoing mail unless he has some to deliver. This carrier put up with ridiculous challenges all the way through.
You can see a much longer video detailing this prank here.
Commenting on Neatorama will earn you NeatoPoints!