Anecdotal, but there's a supermarket chain in the Southeastern U.S. (Publix) that pays their employees a living wage, provides health coverage, and makes a point of letting the customer know that staff (even the folks that load your groceries into your car) doesn't accept tips. The food costs are a little bit higher than, say, Walmart, but closer to that end of the spectrum if Whole Foods is the opposite end. I don't…
That's quite a culture difference with Europe, here they would think that you were crazy if you would do such a thing ...