Quick online search shows it's at least a topic being discussed. https://www.quora.com/Why-do-restau...ur-tip-be-the-food-and-drink-total-before-taxI dunno...having worked in restaurants for quite a while, I kind of feel like if it was a widespread thing I'd have probably heard about it. Granted, I've been out of the food service game for a while, but I don't feel like there's been a revolution in the "paying for the bill" part of the industry in a good long time.