It is only fair that the passengers actually know how the rating system functions. If, for example, you knew nothing about how wine ratings worked, and you saw things with 70s, you'd think "above average," when in reality, the way the ratings are skewed, it is often swill that should be tossed. When I'm given a survey and an excellent product "met my expectations" (i.e., 3 out of 5 stars, according to the survey), it didn't "exceed my expectations" so it isn't worthy of 4 or 5 stars according to definition. But since I know that a driver will face repercussion for what would ordinarily seem like an average or good rating (3 or 4), I just default to 5, unless there's a material defect in the ride, such as safety or a pig sty. I'd rather have the driver try and make a living than out of work.