You can not possibly compare the taco bar to burger king....Shouldn't we draw a distinction here between full-service table waiting and a walk-up counter? Really, how is this taco bar any different than the old Airstream sushi bar? Or for that matter, Burger King?
It's COUNTER SERVICE, people. The food comes in plastic baskets lined with wax paper. 15 percent? Auto tipping has to be relative to the food you get and how you get it. Sorry, but this doesn't qualify, IMO.