It’s not misleading in the sense that they are requiring you to disclose your margins and proprietary information to prove those margins, when they are your competitor. Most sellers are not selling unique items and the ones they would probably compete against are selling the same item over and over again, so they can clearly use this information to determine which sellers they can squeeze the most easily, which categories they should run their own competing product in, demand your prove it so that they can identify your suppliers, by just using information from a few transactions where they decide to damage or lose your product.