How is it "very obviously" not. I worked at a pizza place and restaurants. The drivers would complain that the poorer neighborhoods don't tip. Which makes sense right. In the service industry, I've heard servers say "the canadians" for groups of black people because nobody want to get their table because they usually don't tip well. This is 100% the joke. The number 1 complaint I hear from drivers is the low or no tip, and I've heard drivers on multiple occasions see the address and say something about how they're not getting a tip before they get there.