Just one driver? Just ten? Who decides what the threshold should be? And what happens when Uber and Lyft decide to ban riders for criteria other than their star rating? Other tech companies have begun to ban people for reasons having nothing to do with their behavior online.
If they use their momentary advantage to push out other legitimate options for transit, then there is a good argument for regulation protecting riders.
Maybe Uber shouldn't be making any decisions about users. Just present the rating to the driver pool and let drivers decide who they pick up and who they do not. It doesn't entirely solve the issue of "what is a justifiable reason for rating a rider (or driver) poorly?" but it makes it less catastrophic for users.
