You do not have the right to mail that is misdelivered to you. Specifically, you don’t have the right to USE mail that is misdelivered to you, whether it’s got someone else’s name and your address, or someone else’s name and a completely different address. You always have the right to return it to the post office, or to get the mail to its rightful owner. For instance, if mail to your neighbor arrives in your box, even if it’s got your address for some reason, you would be perfectly okay to walk down the street and give them their mail or call them and ask them to pick it up from you.
You’re also okay if you accidentally open the mail first. As long as you get it to the rightful recipient once you realize the mistake, you’re in the clear. You cannot, however, take whatever information is inside and use it for your own purposes, and you don’t have the right to just throw it away. At least that is the way I understood the case law I was reading.
In this case, I think the post office would have a difficult time pursuing any kind of charges against her even if she’d flat refused to give it back. This particular item reached what I would consider to be more of an “artifact” stage. Had the post office realized that they were delivering a postcard this old, they’d have probably tossed it. They certainly weren’t going to go to the trouble of finding the man like I did. By the way - not an easy job, because the card is addressed to Scott McMurry, but his full name is Dean S. McMurry, and he goes by his middle name. That made it pretty tricky to find him.
I think what might have happened is that the post office might have heard about the conversations we were having on Facebook about it. I suggested that we get in touch with Fedex or UPS and offer them the opportunity to deliver the postcard, and to cut a commercial about it with a script saying something to the effect of “The regular mail took over 50 years to deliver this postcard to the wrong address in the wrong state, but Fedex found the rightful recipient overnight. Whatever you’re sending, don’t take chances. If you care enough to send it, send it with Fedex.”