It won't, and that's not the point here. A judge has been asked to prove that seven commentators are actually clients of the service — otherwise, said comments

It won't, and that's not the point here. A judge has been asked to prove that seven commentators are actually clients of the service — otherwise, said comments were slander. He or she can't ignore that; more importantly, that accusation is almost systematic from service providers who accuse Yelp of slandering them, presumably with non-existant users, and then racketing them to dismiss said comment (in actually, pay to chose which comment to put first). Having the receipt might help clear common issues: the user got the name of the restaurant wrong, the interaction happened before the owner changed, it happened ‘that night’, etc. This is far from an isolated case: all services from the distributed economy (eBay, AirBnB, Blablacar, etc.) have to handle trust and find appropriate mechanism. There has been cases of good-grade racketing on eBay; AirBnB has proven fairly good so far; BlablaCar name itself is a great example of a non-binary rating. Hence the discussion. If users of that service want to get their good back, a small claims court seems more appropriate than a Hacker News thread.