A lot of bad ratings are from fat fingered drunks who can barely see their phone, let alone count stars. Therefore, make it require the rider to solve a math problem to leave a rating less than 5 stars. A problem that requires thinking, not just plugging numbers in to a calculator. For example, find the area of a circle with a diameter of 6 or solve a quadratic equation. This would weed out the drunks and the people who are on the lower end of the IQ spectrum. The people who would rate 1 star for no aux cable won't do so if they have to use their brain to solve a math problem.