John Gravois makes various arguments against tipping. He flags a recent paper on tipping's relationship to bribery:
We investigated the link between tipping, an altruistic act, and bribery, an immoral act. We found a positive relationship between these two seemingly unrelated behaviors, using archival cross-national data for 32 countries, and controlling for per capita gross domestic product, income inequality, and other factors. Countries that had higher rates of tipping behavior tended to have higher rates of corruption.