That example just shows how the remaining IRS employees have never traveled beyond the Beltway.  It says "Individual D receives a Form 1099-K."  The reason tips aren't shown on it is that you don't tip the tour guide when you book the tour, you do it in cash at the end of the tour if you had a good time.  (This is especially true of US tour guides for foreign tourists.)  IRS was afraid to use a barber or beautician as an example, so they pulled this one out of thin air somewhere dark.