@dalias
For those interested, USPS has an optional service for PO box holders to use the post office street address to receive packages from Amazon, UPS, FedEx, couriers, etc.
Amazon accepts a post office street address, as well as a PO box, for deliveries, as do most, if not all other carriers and couriers. The exceptions to this may be for insured, bonded, recipient-only, or other such restricted deliveries.
Some Amazon sellers do not ship to PO box addresses but the post office street address seems to be acceptable.
The post office acts as agent to sign for packages if necessary and packages are held for pickup at the post office for some number of days.
The packages are delivered to the post office and do not go to the regional sorting facility. As far as I know the USPS does not permit forwarding of packages to other addresses.
Many post office box lobbies are visible from the outside, where people can loiter and watch a box or boxes of interest for people to collect their mail. Loiterers are usually easy to spot.
And that is about as much as I know about it.