it doesn't happen all the time.buyer has to see the reviews which is been posted by the customers who have purchased from the seller. if the customers have left the negative reviews i think another customers should not buy from those sellers. because they are cheating to us. eBay is right in this way because eBay shows you all whoever are the buyers positive as well as negative factors. it does not mean that feedback will always be negative apart from eBay. it depends upon the trustworthiness of the seller as well as the product.