Sure, there will be a dishonest customer here and there. They are far outnumbered by the good, honest buyers.
I too have had items that say "delivered", but they haven't. While I fought with USPS, I resent an item and recovered my item from USPS. (I was actually lucky to get it back; it was unexpected). I would NEVER leave my customer without their item. It is my responsibility to get them their package. If a courier (USPS, UPS, FedEx) fails, I fight with them. Never the customer.
If you bought something from Target, how would you feel if it didn't come and they told you, "Sorry, USPS lost your package. You're out of luck!" then hung up. How would you feel? Sure, I don't have the financial cushion that they have, but sure as heck, my customers are going to get their items.