Reminds me a little of the scenario where people bizarrely ask a forum if they can bring their dog to a hotel, some random person says "yes" and then you wonder if the hotel declined to accept the dog if the owner would say "well Bob off the internet said it would be fine"
Well I was going through and approving the reviews (just for stopping spam reviews), and I found a guy leaving a review explaining that he's very sorry but he hasn't had time to use the product as his wife has come down with a bad case of the shingles - I seem to remember he went into quite a lot of detail and obviously hadn't realised this review could have been made public.
So, the reward for helping with the forum are some badges and a chance to be Google's beta tester, and it appears to be working? Maybe they can launch some sort of mechanical turks service in the future where the workers are paid with this "rewards" instead of money.