One problem I have seen over the years is when two very different books have the same exact ISBN. Years ago I ran in a listing that about half of it was Harlequin romances and the other this tome that only a scholar would love. The ISBN had its beginning numbers the same as all other Harlequin books so they owned that number. One could only assume that the other book printer made a mistake when printing or writing down the ISBN the first time and it never got fixed. I saw that at least once a year. A combo listing with two very different books.
I think that is one of the biggest reasons that I list one by one still even as a pro seller, is wanting to be sure that what I am listing is on the correct page and if the page needs fixed I work on that as well. It takes me a lot of time to list, because I am cleaning up others errors. I prefer not to get SNAD refund requests.