I once purchased a nice, and somewhat pricey, custom cue from a dealer on the internet. The stated ferrule diameters were 12.75 mm each. When I received the cue, it looked very nice, and the shafts indeed felt smaller than 13 mm, but I did not actually check the diameters. Shortly thereafter, I decided to sell the cue in favor of a couple of other cues I owned at the time, so I listed it on eBay stating 12.75 mm ferrules as I had been told. It sold for a not bad dollar, but I was contacted soon after by the buyer, who is also a known cue dealer, who stated the ferrules were, in actuality, noticeably smaller than what I stated, after he used a digital caliper.
To make a long story short, he asked for a partial refund to make up for the shaft diameters being smaller than he was told and I am sure, at least in part, for being less attractive for resale. Ultimately, although I was misinformed by the original seller, I was the one who bore the burden of responsibility for listing the cue with the stated dimensions, and for rectifying any resulting buyer dissatisfaction for the transaction. His refund request was a very reasonable one, considering he could have just asked, legitimately, to return the entire cue. I did refund the requested portion and, to my knowledge, no harm was done between us. It did leave a bitter taste in my mouth for not verifying the diameters as soon as I received the cue, but it is not a lesson I will soon forget.
In a nutshell, it should never be the buyer who assumes any loss when a seller, either knowingly or unknowingly, misrepresents an item. Without consistent integrity on the part of the seller to look after the legitimate needs of his customer, there is no way for any of us to feel good or secure about dealing over the internet with people we are likely never to meet face to face.
Ryan