I guess I just never really thought about the logistics of delivery to a Post Office Box before but only the United States Post Office can deliver to PO Boxes. If you think about it, it makes sense because the only way someone can access the box is with a key (you) or through the back (the post office), UPS and FedEx can’t very well leave the package outside a bank of PO Boxes in the hopes that you, and not some enterprising thief, picks it up.
While I’ve never FedEx’d or UPS’d a package to a PO Box before, I bet that their software or their people would probably notify me that they couldn’t delivery… but what if they didn’t? What happens if you try to use UPS or FedEx to deliver? Return to sender? Anyone know?