If we determine that there is insufficient customer demand for your product, we may choose to no longer carry it. In such cases, we will attempt to return all Products to you.So what they are saying is that if not enough of your books sell through Amazon that they may or may not return any to you that they have, and they aren't going to tell you how few sales is too few. In other words, they can just cut you off without any warning.
Please be sure to update your return address so that we can properly process returns to your organization. This address should be a valid US street address rather than a PO Box. You can update your address by going to Settings->Return Address. If we have an outdated or incorrect address for you, or if we cannot charge to your freight account, we may liquidate the Products and keep the proceeds, destroy the Products, or ship the Products to you and deduct the charges from any payments due to you through Advantage.
We apologize for any inconvenience but at this time we cannot provide you with any item level return information prior to the return being processed.
I suppose I shouldn't be surprised. Amazon is terrible for small-volume sales. A publisher barely covers the cost of the book by the time all the discounts and fees are applied. Now, in addition to preventing you from making any money, they may even prevent you from presenting your book to the public at large through a company which at least provides credibility.
I wonder if my sales will be enough to keep me in Amazon. I sell about four a year there, and they only keep one in stock.
If you are a small seller, just be sure that your return address in your Advantage Central file is up to date!