When I’m travelling a lot I eat out all the time. I’m always reminded of Loudon Wainwright III’s song about the interface between consumption and production. Tipping is one of the places where this relationship is made absolutely clear. You have the chance and the choice to make someone’s life easier and their night better. Or not, the choice is yours.
I guess that the right thing to do here is to follow Loudon rather than Mr Pink. But you can judge for yourself who makes the most persuasive argument.