system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why won't companies ship to P.O Boxes?

Just overall, I am wondering, I tried to google it, and could not find a easy answer, but why won't most companies ship things to P.O Boxes?
gpt
The law says only the United States Postal Service may deliver to post office boxes.  Also, if the package needs to be signed for, a PO box cannot do this.

On the other hand, it's not unusual for companies such as The UPS Store, FedEx/Kinko's (not to mention many mom n' pop stores) to offer mailboxes that don't belong to the USPS, and one can have packages *not* shipped by the USPS delivered to such boxes.  And during business hours, there *will* be someone there to sign for the package.