Interesting look at lots of research on tipping: <a href="http:&#x2F;&#x2F;freakonomics.com&#x2F;podcast&#x2F;should-tipping-be-banned-a-new-freakonomics-radio-podcast&#x2F;" rel="nofollow">http:&#x2F;&#x2F;freakonomics.com&#x2F;podcast&#x2F;should-tipping-be-banned-a-n...</a><p>(You will agree that tipping is racist by the time you finish listening.)