I've heard this a lot. When I look at reviews anywhere where there is a star rating and text review the only useful reviews tend to be 2-4 star reviews. 1 and 5 star reviews seem to have a tendency to be outliers or people who are really upset about something that most people won't care about. For example 1 star restaurant reviews that waited for someone to take their order and left because it took too long. I wonder if that could be applied to weighing the ratings accordingly. I have no data to test this unfortunately.