What you do have to worry about is the infrequent case where your package was delivered to the wrong party by the USPS and the receipient simply kept it. That does occasionally happen. Back when I was trading blades frequently, I ripped open a USPS priority box that was delivered to my place and found women's underwear that were intended for the folks at the same address on the NEXT STREET OVER.
So did you keep the underwear?
