Und - vor allem - es ist eben ein "mandatory" gratuity. Das steht in der Karte und das ist dann quasi wie eine AGB.
auch dies ist - wie Du em Link entnehmen könntest, offenbar heftig umstritten.
Im übrigen kannst Du auf der von Dir zitierten (und nicht verlinkten) Seite jede Menge Posts lesen, daß nach "amerikanischer Denke" umfangreiches Tippen offenbar sehr wohl Standard ist und die wenig-Tipper die Ausnahme sind. Auch der Typ aus dem von Dir zitierten Vorfall wird im Gesamttext ja als ziemlich großes Ar....ch eingestuft (der eben nicht der "amerikanischen Denke" entspricht).
(die Quelle ist hier:
https://www.quora.com/What-happens-if-you-leave-a-restaurant-without-leaving-a-tip )
Amerikanische Denke ist das da:
"On these occasions, your first instinct is not to leave a tip. But, we already discussed that tips are your server’s living wages. If you don’t tip your server, they aren’t making a decent wage, right?
Here are a couple suggestions if the service was awful:
If the food was slow to arrive, complain to the manager. Let him know his kitchen was slow. This isn’t your server’s fault. So, tip the server.
It took 10 minutes to get a new beer. Again, this may not be your server’s fault. Perhaps the bar was backed up. If so, this is on the manager for not staffing appropriately.
If your server was rude, definitely let the manager know. You still want to leave at least a 15% tip. After all, your server did bring you your drinks and your food. They fulfilled their basic requirement.
Here’s an example. Suppose you are an attorney. Your client comes to your office for a meeting. You’ve had a bad day, and you are incredibly grumpy to your client. You do your job, ask the questions and make a game plan for your client. But, you weren’t overly friendly, and you shuffled him out the door.
Do you still get paid? You bet you do. The bill goes out, and you get paid. Using this example, you can see that it’s only fair to tip the server.
Bad service is not an outright excuse to leave a small tip or no tip at all. (tweet this) Bad service is a reason to leave the minimum 15% tip. Good service deserves more.
Lastly, if you can’t afford to tip, choose a less expensive restaurant or one where you don’t have to tip at all."
Quelle:
https://restaurantengine.com/not-leaving-the-right-tip/