Thank God for the guarantee. Wish I could say that they were the only ones. There are a lot of scams lately on eBay. IMO they are only slightly better than Craigslist at the moment.
Another one to look out for are hard to find/desirable pieces, not just posters, where the user is registered for 6 months to a year with a few feedback comments but their user ID always ends in a dash number. Many look like auto-generated numbers to begin with, example: r57390281-2 or somename-6. The items images are older images from other users usually a year or more old so they are no longer in the system or I have seen quite a few that were taken from Yahoo Japan. In most cases and the price is low but not too good to be true low.
These are usually scams from what I believe is China where they either do not actually have the item for sale or are selling bootlegs of some sort. More often than not they mark them as shipped with no additional information and the items never arrive. Ebay sometimes catches them before you contact them about it but even if not they have always canceled and refunded immediately without waiting for responses from the seller to the dispute as they know the deal is bogus.