Satya's blog - The USPS mis-directs mail.

But they handled it pretty well. I sent a postcard from the US to India, and I posted it at the post office by handing it to a human.
Someone read the wrong address. The next day (today), I got the postcard back in the mail. "Delivered". So I took it back to the post office, where the same human was very nice and re-injected it back into the queue. Yay.