That's the thing, a tip to me at least has always meant to be a surprise, a "you've done well, here's a bit extra" kind of thing. When it then turns in to an expectation, you're removing the element of people wanting to go above and beyond as they're potentially getting a tip anyway. A tip is a tip, it's not a bloody fee.
Also service charge can get in the sea.
Also service charge can get in the sea.