Based on the facts outlined in the original post, the seller's responsibility is fulfilled. If one desires absolute certainty of delivery, then a service that requires the signature of the recipient is mandatory.
I once shipped an item via USPS Priority Mail Insured. This service requires the signature of the recipient. The USPS tracking showed the item had been delivered, but the recipient had not received the item. It turned out the apartment manager signed for the item, and held it, but did not notify the renter that the item had arrived. It was against USPS rules that the apartment manager sign for the item. The USPS letter carrier screwed up. What are you going to do? Eventually, after a few harried emails, the recipient discovered the item in the manager's office.
Bottom line is that according to the original post, the sender's responsibility is complete. It's up to the recipient to agree to and pay for insured delivery with signature required. I always insure as part of a sales agreement that if a buyer chooses to use a shipping method that does not requires a signature, then the buyer agrees that my responsibility for the safe delivery ends when I transfer the item to the shipping company.
I once shipped an item via USPS Priority Mail Insured. This service requires the signature of the recipient. The USPS tracking showed the item had been delivered, but the recipient had not received the item. It turned out the apartment manager signed for the item, and held it, but did not notify the renter that the item had arrived. It was against USPS rules that the apartment manager sign for the item. The USPS letter carrier screwed up. What are you going to do? Eventually, after a few harried emails, the recipient discovered the item in the manager's office.
Bottom line is that according to the original post, the sender's responsibility is complete. It's up to the recipient to agree to and pay for insured delivery with signature required. I always insure as part of a sales agreement that if a buyer chooses to use a shipping method that does not requires a signature, then the buyer agrees that my responsibility for the safe delivery ends when I transfer the item to the shipping company.

