The majority of waiters/waitresses I know may complain about their hourly salary, but in most cases they rely on the money they get from tips than their normal pay. Why? Because although they are suppose to report their tips not only to their boss but on their taxes, few do. And that means more "unreported income" for them.
Now, the flip side to this argument is if the waiter/waitress doesn't bring home enough in tips to make ends meet their normal pay usually isn't enough to make up the difference. So, it's a catch-22...damned if they complain too loudly, damned if they keep their mouth shut and don't make enough in tips to cover their expenditures. To put it mildly, most folks who work for tips would rather get paid that way than on a typical average wage because depending on how things go (i.e., holiday, special occasion, major sporting event, etc.) they stand to make more money in a few days than some folks make in a week at or even above minimum wage.
I guess when it really comes down to it, if you're good at what you do in whatever industry you do it in be it restaurant, night club, cabby, barber or even shoeshine boy, the tips should role in. And if you're able to keep most of it all to yourself, you make out like a bandit...literally.
To sum it up, I'd say tips are "extra" income for "a job well-done". So, my answer would be "NO". An honest day's work for an honest day's pay. But when you're being paid for less than your worth, the customer's make up the difference which really shouldn't be a "difference maker" in pay at all. It's earnings- an added bonus as it were - for good customer service.
Note: I mistakenly voted "Yes" when I meant "No".