If you ever notice that I say chicken oddly, then know that it is because I worked at a fast food outlet called Chick-Inn every Friday night, Saturday day and Sunday night for some time in my teens. It was probably about a year, but in hindsight it felt like much much longer, especially after the Gypsy Kings CD got stuck in the stereo and was thus on All The Time. I used to twitch whenever I heard Bamboleo but I'm okay now.
But I digress.
This place did delivery as well as eat-in. I was a "cashier" which means I was at the counter, took the orders and money, put together drinks, soft-serve ice-cream and jelly cups and other bits that were pre-prepared, gave people their food and often ended up in the kitchen helping out with putting together the burgers and boxes of chicken and cooking stuff and so on. Dishes were for drivers, yet I ended up often taking their phone orders, preparing their bags and doing those dishes. I never got a tip over the counter, and that was fine.
Some years later I found out that the drivers used to routinely get tips on the doorstep, sometimes several hours' pay extra a night. Never a cent was shared. This was their due apparently. Despite the backroom work done by others to get those orders out the door and in to the cars asap there was no acknowledgement of that (and not just in money either but that's something else).
And guess what? The drivers were almost all male and those of us working the cashier jobs mainly female.
I've worked in other hospo and service jobs too, never as the only money that I needed to survive, luckily. As someone who did not fit the physical stereotypes for shall we call it extra appreciation (and sadly also harassment) I don't think I ever got a tip. Again, that was fine.
It was fine because I was paid a (relatively) fair wage which was not undercut, or reliant upon top ups, from tips.
Hospo and service jobs already have a massive power imbalance and exploitation is rife. The Customer Is Always Right (even when they harass you or hit you or are unreasonably unreasonable and you want to spit in their food but you don't or maybe you do but you make sure no one else sees). Smiles Are Free (but are they really, for the smiler?).
If We Don't Take Care Of Our Customers Someone Else Will (so give them whatever they want in case they flee and tell all their friends about our awfulness nevermind how they treat you). And many other Inspirational Customer Service Quotes that reinforce the lowliness of the person doing the serving, and the supremacy of the customer, and the role of the manager as champion of the poor downtrodden arseholes with the money.
And there's the vicious cycle - you aren't worth much because you aren't paid much, and you don't get much in tips so you are obviously not worth much, and around and around we go.
So yeah, tipping as a way of improving customer service? Not likely. Tipping as a way of making those working in hospo and service industries even less powerful and more discriminated against? Very very likely indeed.