Oh yes, yes, yes. I had one just last weekend who received his item and then emailed me threatening to report for some sort of Ebay violation unless I gave him a partial refund immediately. I knew I had done nothing wrong and their was nothing wrong with the product so I wasn't particularly sweating it. I've had three or four of these in the last two months. It seems to be going hand in hand with the slow/non-paying bidders.
The other trend I am seeing, which is annoying to me but might not bother other sellers, is the increase in the use of Paypal echeques with their incredibly long wait time. In almost everycase it is relatively new Ebay/Paypal users issuing them. In two recent cases, after I waited 8 days for the cheque to clear, it "failed". Yes, that's right, more non-paying bidders.
Just one bad customer can wash away the sweet taste of 25 excellent ones. Sigh....tomorrow is another day!