In England a tip is a reward for good service.
Well, it's for service that's not deliberately bad, anyway. Even if the food gets dropped down the back of your neck and you get three liver and bacons when you asked for a fish pie and a soup, people will still tip as long as the waiting staff seem to have been doing their best.
In England, a tip will be about 10%, and it's entirely voluntary. It may be given out of either gratitude or pity. A desire not to look mean comes into the equation, too.
A service charge takes the place of a tip, even if the waiter is exceptionally charming, competent and handsome.
A discretionary service charge...
A discretionary service charge?
But discretionary means...hang on, I'll look it up...yes, here it is: having the ability to decide as one sees fit.
A discretionary charge???
Oh dear. I can forgive bad cooking, but careless language is beyond the pale. I doubt I'll be back.
Word To Use Today: tip. The Collins dictionary suggests that this meaning of the word tip comes from the Low German word tippen, to strike lightly.
No, I don't understand it, either, but there you go.