My parents had this problem with mail being delivered to their home intended for my deadbeat brother (who had apparently intentionally left no forwarding address when he moved from one apartment to another, so creditors went back to his last known address, which was my parents' house). They talked to the mail carrier about it after months of returning things to senders, and the post office eventually stuck a note on the inside of the mailbox saying "nothing for Joe Smith" to remind the carriers to sort the mail themselves at the house and pull out anything addressed to my brother. It's a lot of extra work for the mail carriers, though, so I'm not sure they'd be willing to do this in every case.