I could see a decent tip after a class or tour ended or something along those lines, for good work; but I wandered into a coffee shop the other day, while on the road; poured my own damn cup and used an automated kiosk for payment, and was given the option of leaving either a 15, 20, or 25 percent tip, for the slacker with a bull ring through his nose and a tattooed blue ankh on his forehead, who acknowledged no one who came into the place, and sat busily scribbling in a notebook.
Yeah, that works . . .