* Collect positive reviews on a cheap article.
* Change the product, but not the article ID. The new article then has the reviews of the old one.
* Finally, they lock the reviews by setting the article to "not released yet", even though the product is for sale.
That way, you get positive reviews for a shitty product and customers can't add negative reviews.
Amazon don't do anything about this, even though it's clearly deceptive and, at least here, against the law.