No, they don't. You're trying a false equivalency between a bribe and gratuity. A bribe happens before the service is provided and the service is contingent upon the bribe. Gratuity is post factum, technically based on the quality of the service provided.
Let's take police officers in México, for México, for example. One needs to pay bribes to get anything done. On the other hand, they have almost zero job protection, have absolutely crappy salaries, most of the time have to buy their own uniforms, their own gas for the police cars, and so forth. And on top of that, they have to contribute to "upwards bribes", so they can keep their jobs.
It might not be identical to the situation of a water at a café, but jeez, does it rhyme with it.
Tipping should be banned. Waitstaff at a restaurant should be considered like any other employee. Tipping someone because they went "above and beyond" should be considered as an insult, because it's literally a bribe, "I'll give you something extra for your trouble".
Alas, it's a bit too idealistic of me to expect that to happen.
Yet? It’s always awkward at the end of the school year when we are asked to prepare gifts for the teachers. Like, how do you do that without it appearing as a bribe/entitlement?
Most of the time it's to get them to actually do their job; shitty pay, bad or nonexistent oversight, corruption (or just "bribes") in higher levels too, conditionally applied rules, etc...
That creates a de-facto auction for their time and service, you (and what you're adding on top) vs. everyone else (and what they are adding on top). There's an unofficial "price list" depending on how quick and thorough you want things to be done.
"Tipping culture" easily slides into "bribing culture" when it becomes an expectation, regardless of what the Supreme Court says about it.
Tip 0 and see what kind of service you get the next time.
I used to work food delivery and naturally the customers ordering takeout at fancy restaurants would always tip 0 to the restaurant even if they tipped me for delivery.
I quickly found myself ignored by all the workers at those restaurants, orders take an hour extra to fill, no one talk to me, etc. eventually I learned to tip out of my own tip because my next service is contingent on the prior tip.
I live in an affluent area and my daughter works in food service. She says the people she knows to be wealthy are generally the worst tippers (often 0%). I have stuck with 15% even though that is below the suggestions on receipts these days and she tells me that's high for the restaurant's average.
Let's be real. You are creating a conflict of interest. If I take "tips" from my customers, my employer would be pissed. The only reason we are considering this to not be corruption is because it's a system foisted on them by management to reduce their costs.
In more egregious instances in food service I saw employees trade goods for tips quid-pro-quo and cut the business entirely out of the transaction.
I work for the government and we are not allowed to accept tips. Even if there is a technical difference between a bribe and a gratuity, it is too easy to misconstrue a tip as a bribe (by either or both parties) and it is too easy to frame a bribe as a tip.
There are plenty of situations where you pay up front and fill in the tip before service is actually rendered. I've had situations where I tip the standard and get bad service (eg missed side orders).
It's irrelevant if you pay people before or after. You can't tip the police after they perform some sort of service. You're still trying to influence them with money.
It should be based on quality of service, or at least on some service being provided, but what has now become the norm is the expectation that you pay a tip (and a hefty percentage one, not just a dollar in the tip jar) just for buying a food item at the counter, with zero service provided.
I'm not saying tips should be banned but there certainly is a "cultural aspect" to tipping...