i send only registered, so if the Customer went to the Post office or talk to the Postman, he can of course claim the Damage. To Point the truth, its just too much Work or maybe the People need too much Intelligence for this. Its easier to get the Money from the Seller back, thanks to Paypal & Co. If i get a damaged Parcel, i can go Several Days later to the Post Office and Reclaim the Damage, fill a Damage Report and let the Sender make a Claim, too. With German Post System it is relative easy and with Lost Letters/Parcels its really easy, the Customer don't need to do anything (gladly).
I'm wondering why spend 2x much Postage for Stuff, when the Customer is too lazy/Stupid to reclaim it afterwards, since they paid it?
But it depends of the Worth, if you have a Parcel about Hundret Dollars or Euros, it looks Different, of course. But till 100 i never had Problems with German Post.
I got several Times broken Vinyls from the Post Man and last Days the Hermes Deliverer told me to open the Parcel, since he heard a Cracking inside the Parcel. Gladly there weren't anything broken, but if it were i had make a Claim directly with him.