When I post items overseas I always take an iphone photo when the package is sitting stamped & ready to go on the post office counter. If it is slow to arrive & the buyer is sending me anxious messages I can send them an image of their goods just about to enter the postal system. I think for a genuine buyer that will give them some reassurance, that at least I'm not cheating them. This relates to the OPs question in that it might dissuade the buyer from impetuously starting a paypal claim.