A lot of "review" sites are cons anyway.
I go on TripAdvisor a lot and it is obvious many hotel and restaurant reviews are fakes.
They are people who register for TripAdvisor and do a review the same day, but then never do another review again.
I went to a B&B in Devon a few years ago and on TripAdvisor almost every other "review" for that B&B was by someone who only did one review.
I spoke to the B&B owner at the time about computers and he was very knowledgeable so I guessed he was doing many of the reviews.
I did report it to TripAdvisor but they did nothing about it.