Hard to believe, but yes. But you should get as many ratings as possible, an interrupted 'chain' of ratings. Also, you need to predict a minimal and maximal number of ratings you've got. Taxi drivers don't always rate their passengers. To my experience, only half of them get ratings. (Maybe drivers are just too busy or lazy, but this is OK.)
All these tests were executed with assumption that you have at least 1 ride and at most 30 rides. YMMV. Fix this for your data.