Many of you may know this method by LE and avoid it. I learned and now will always avoid it as well.
A few years ago a friend of mine ordered some stuff to his box from overseas. Small amount but evidently still enough for them to bother with. Tracking showed it not even touching customs, it was an express that arrived at his PO box 4-5 days after order max.
He would usually let it sit a couple days anyway and this time would be no different, he had work for 2 days straight and then on his day off he was going to grab it.
The next day at work he checked the tracking to see if it was awaiting pickup as I believe the last update before that basically was at a very close by hub. The tracking showed undeliverable as addressed, return to sender. Or call to schedule pickup or redeliver. Which he did and that's how they got him.
Basically be careful with those return to sender. I'm aware many are mistakes etc. but me personally I would just let it go and forget about it.
Can't even get myusps to work with my Po but thanks OP