A FedEx customer dosen't really buy insurance. He ups his declared value from the basic $100 to a certain amount, and then pays additional fees for the carrier to be liable for the extra amount in case they destroy or damage his shipment. It's up to the customer (shipper) to prove damages, and there are exceptions and exclusions. This is outlined on the back of the Fed Ex airbill, available at any Fed Ex drop box (and probably on their website). This constitutes an agreement between the shipper and the carrier.
