&gt; In fact I don&#x27;t even have to pay (the tip) if I don&#x27;t want to. I still get a better driver, because they try to get me to tip.<p>You&#x27;ll begin to get the reputation that you don&#x27;t tip. Why would anyone pick you up then? You&#x27;re essentially forced to tip if you want continued, good service.<p>&gt; Well, that&#x27;s easy to solve: don&#x27;t allow drivers to rate passengers.<p>That&#x27;s not a solution though; that&#x27;s a hack to remove an undesirable affect from another feature (tipping). Just like drivers can be rated by passengers the inverse is also very important. These are still people&#x27;s private cars after all; do you really want no way to rate the guy who trashes someone&#x27;s car or is just an asshat?