Well said. I disagree with the article title, due to my experience with delivering pizza.
We all certainly knew the non-tippers. And they almost always were in the wealthiest neighborhoods. So once you go to a house 3 or 4 times, and get stiffed (or hear about it from the other drivers), they become your lowest priority.
Working class and poor neighborhoods almost always got better service and faster food delivery from us because we knew they tipped more often. The non tippers typically ended up with cold pizza and dropped 2 liters cause we didn't give a crap.