This is just our way of doing things, so it might not be the best for everyone.. but one whatever item you sent, we would have paid for either the 100 or 200 dollars of insurance for it. Using a setup on something like Endicia allows you to do this for quite a bit cheaper than the normal USPS rates (there are other companies that do this besides Endicia, but I recommend them).
If a buyer is going to claim that they didn't receive the item, then they should be more than happy to sign a little 1 page emailed form stating that the package was lost in transit.
Often times, in situations like these, that is the only way to get compensation for a package that just "disappeared". If the insurance company wanted to investigate it further at some point.. it would be the buyer who would be seen at fault for signing a document under false pretenses.
We always go for the insurance over signature confirmation. The cost (depending on the amount of insurance) always came out to be very close to the sig conf, with the additional benefit of compensation should the package actually fall into the cracks of the earth.
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