I've never seen it either. I've heard of it though, but only in wealthier areas. Working class people don't have the luxury of deciding to pay extra to alleviate human suffering - it's the same reason walmart consumes all other choices; the average person chooses the cheapest option because they're already scraping by. A more relatable take would be to just opt out of eating at places that demand tips -- I already do that, but only because I can't afford to eat out anyway :)