What you describe in your last sentence is, I think, exactly how restaurant tipping works. It's best to look at it as a 15% labor tax, with an optional 5-10% upcharge if you're happy (or have a general policy of retaining a reputation as a good tipper).
Another similar example (probably outdated): airport skycaps.
An example of a tipping system in America that doesn't work that way (yet) is hotel housekeeping; a surprising number of people don't even know that there's a tipping custom there at all.
The "quasi tax" thing sounds alarming, but it doesn't bother me at all; it's just another way of expressing costs and prices. Things will cost what they cost one way or the other. If tipping becomes so common that everything has 5-15% tacked onto it (I doubt it'll happen, but we'll stipulate), base prices will fall. Businesses can't simply banish demand curves! There is ultimately a market clearing price.
