All the investigator sees is that someone went to a website with your name on it, bought product X, and received a counterfeit of product X instead. It doesn't matter how that happened; all that matters is that your business enables counterfeit goods to find a market. Of course if you run a business that sells via Amazon you have to specifically opt out of this inventory mixing, even though it increases your costs. Either that or you shouldn't do business via Amazon at all, or you should gang together with other businesses and force Amazon to change it's operations. But no matter what you do it's likely to increase your costs.