While that’s absolutely terrible, that’s also what tracking numbers are for. You can input tracking numbers directly into PayPal, and it prevents some of those claims from being investigated depending on the level of tracking. You don’t have to require a signature to get a picture of the item at the buyers front door.
I had a member here buy a carburetor from me, paid for through PayPal as goods/services. I shipped it tracked and insured. He claimed he never got it, filed a claim, and demanded his money back. I put the tracking number into PayPal, showing it was delivered directly to a person at his address. Magically he replied he had the carb and dropped the case before they found against him.
Before I ship something out as a seller I take a new picture of the item sitting on the box, one in the box with the packing, and one of the sealed package with the label, and they all go tracked and insured for the sold value or better. Sucks, takes a little more time, costs more money. But it stops the bullshit, and helps with the insurance if it gets damaged en route.