After reading Ghastly's response (and the example of the 'break it you buy it rule' is noted), I was waiting for Sharon to pipe in about customer service.
"We all know the postal service plays football with the packages, USP and FedEx too, it's the nature of the beast. It has nothing to do with a neighbor, kids, or anything else, we KNOW the boxes are going to get tossed around...so, when you pack something, especially something expensive in high grade, you need adequate packing around the items to protect it....
...I've learned to insure ANYTHING I sell, even if the buyer doesn't want to pay for it, that is over the amount I would feel comfortable reimbursing the buyer for in case of a problem."
I think you've hit the nail on the head here in being more proactive in high-value dealings to avoid 'he said' situations like we are seeing here. $5 down for insurance would have likely seen a resolution to this off the boards...