You can't control social media! Stop it! Stop it! Stop it! The reason user review sites like Yelp and Trip Advisor work is because people are free to tell the world how good or bad your product or service is. Amazon ratings are hugely important to products. The site; SEARCHENGINELAND.com released the stat that "79% Of Consumers Trust Online Reviews As Much As Personal Recommendations (source)". The latest comedy of marketing madness is the policy of the Union Street Guest House that states; "If you have booked the inn for a wedding or other type of event . . . and given us a deposit of any kind . . . there will be a $500 fine that will be deducted from your deposit for every negative review . . . placed on any internet site by anyone in your party." (NY Post report).
The result so far has been a flood of 1 star reviews on their Yelp page. I have already seen the typical BS excuse that brands try to make 'this was all a joke, we didn't mean it'. That is another tactic that does not work. The bottom line is you can't control what people say and any attempt you make to control the voice of the customer will backfire on you.