Comments and tips,
1."Overinsuring" is not necessarily insurance fraud. I just sold and shipped a preamp that now sells new for $5K. I did not sell it used for that, but I insured it for that. UPS treats items insured for $5K or more as higher value items and requires special procedures for drivers, and I believe for handling the package all the way down the chain. The higher value insurance in this case was a small price to pay for supposedly more careful shipping service.
2.Anyone who doesn't want the problems associated with damaged goods and dealing with shipper's insurance, should get in the habit of double boxing electronic components they sell. I routinely purchase a second box a little larger than the first from the UPS store, and double box all component sales, whether the buyer pays for it or not - geez, it only costs 6 bucks! As stated above, try to get about an inch of styrofoam or bubble wrap in the space between the boxes, especially for heavier stuff. Most buyers will also appreciate that the original Mfg's box inside is not the one getting beat up.
3.Something I have learned from other experienced Audiogonners is that most believe it is safer to ship via air, even the 2 or 3 day variety, as the package is reportedly treated better than a "ground" package.
4.I believe I have had relatively fewer shipping problems by subscribing to the idea it is the seller's responsibility to deliver the item safely to the buyer, then treating the packing, insuring and shipping as carefully as I would want it treated for items I purchase.
Just my experience, YMMV.