I think it's the same to the employee, whether wages or tip income would be taxed as ordinary income. Not positive. If there are cash tips that aren't reported though of course it's probably 0% except for that one honest person. Who uses cash these days though?

Personally I think they should do away with tipping and just charge enough to cover their labor cost. It annoys the shit out of me when you go to counter serve places and the payment terminal has a preset tip to 18% or more. You feel guilty because you are standing in front of the minimum wage earner who you don't want to short but effectively you are paying the owner because they are the ones supplanting wages with tip income and pocketing the difference. Basically that's why you are seeing so much of it now because owners can keep listed prices lower knowing they will cover part of their costs with tip revenue on top of the bill.