Should Tipping Be Banned?

Why do you tip a doorman, but not the man behind the corner? – „Should Tipping Be Banned?“: I am just listening to one of the most popular podcasts of @Freakonomics – very worth listening: http://freakonomics.com/2013/06/03/should-tipping-be-banned-a-new-freakonomics-radio-podcast/  And, guess what: Good looking, blond, slender and big-breasted women in their 30s get the highest tips.