I don't see how the recipient can be forced to pay for it if it was shipped to him. It's the company's mistake, and the recipient should not be forced to take any action, including the "inconvenience" of calling/emailing them, and or bringing their item to the post office for them.
If I own a company, and send out some items to people, and they're forced to pay if they do nothing, then I'd send out duplicates all the time. Some will return it, but I can count on the laziness of Americans to not send it back, or the greediness of them not to send it back, and wallah, I'm making a killing selling extras of my product that I don't want. I think the law protects buyers from that.
This also happened to my father with magazines that he did not order or pay for. He's an honest man, but felt it would be wrong for the company to make him return the item (even if they will pay postage) because of their mistake. Just think if this happened almost routinely, with multiple companies.
Wouldn't it get pretty annoying and piss you off if you were continually bringing things back that were accidentally shipped to you? Especially if they were of no value to you.
I can understand if a mistake was made with a reimbursement of funds that may have been mistakenly put into your account, and later taken out, but still a notification would be in order (actually happened a lot in the Military).