As an experienced buyer/seller on eBay, I can agree with all that is said here. The buyer is usually the one protected in the bargain. I bought several items from a seller, never got the items, and got my money back pretty quickly. On the flip side I sold a bunch of comics to one buyer and she claimed she never got it. I know I mailed the item and I always print the address clearly on the envelope so there's no possible way to misread it. She claimed she never got the item after I asked her to wait another 2 weeks in case the post had screwed up. In the end I was forced to refund the buyer (or namely, eBay did it for me)
Another buyer got her book late but in this case it was clearly a post office screw up, as I had mailed it several days after she paid, and she finally got the item. She had opened a complaint against me but fortunately was willing to wait, and closed the case after the book finally got to her. I can understand buyer protection because some sellers are unscrupulous or haphazard with mailing, but I think the seller needs some protection as well because you can see how easy it can be for a buyer to exploit a seller just so s/he can get an item for free.
So yes, Chris could get pretty screwed if he sold the violin to certain buyers.