> It is an unfair or deceptive act or practice and a violation of this Rule for a business to represent, expressly or by implication, that a website, organization, or entity that it controls, owns, or operates provides independent reviews or opinions about a category of businesses, products, or services including the business or one or more of its products or services.
As I read it, the 5-star review systems on Amazon.com and Walmart.com would be categorized as unfair under this rule, since both companies sell their own products in addition to having a rating system on their website. I'm not sure whether that's intentional or not (and I could be misreading it, IANAL).
[0] https://www.ftc.gov/system/files/ftc_gov/pdf/r311003consumer...