I'm probably the wrong person to chime in on this, as I've been an obscene tipper when I receive adequate to great service. Some of you are witness to this. (I know how it works......). My fault is in not carrying cash very often and the damn debit card that they HAVE to declare. I try and offset this.
It is true, in the food beverage industry their minimum wage is nothing, based on the "tip" portion to make up at least the difference. I think, though, if I remember correctly, if a certain worker did NOT make the minimum wage for hours worked with their compensation and declared tips added for a certain period of time, the employers had to make up the difference. Dunno how thats enforced, but that is the law as I understand it. But as an employer, if I have anyone NOT making that minimum wage consistently, they are probably going to be promoted to customer very quickly.
Now, most bartenders and waitresses (Waiters) I know give excellent service. I recruited every outstanding one I could, and most of those were making far beyond what I can offer to start in retail. I know bartenders making ( some on, some off the books) in excess of $15 an hour for a part time gig.
Tip how you feel you should, but understand the system of their compensation and greed of their employer knowing that. Etiquette and some group of snobs that dine out every day in NYC cannot tell you what the magic percentage is and how to guage what.
My Novel for the day.............

Ray