Let's reframe it another way - would you tip your Chorus technician working on your install or fault? Would you let Chorus say "Sorry, we just pay the staff a retainer, you'll need to pay the technician based on how you think they performed today."? Technicians are paid a fixed price per task these days in the majority of cases, so that's almost certainly an industry where it would fit in, but it's absurd. We don't need that nonsense here.