When I was a server (20-30 years ago), the computer tracked our sales. When I went to clock out it gave me the total amount of sales for all of my customers - say in a 6 hour shift it was $620.55, it then asked how much I was claiming in tips to add to my gross income (so it could calculate my taxes). It wouldn't accept any number less than 10% (again years ago) - I don't know if that was the type of program my restaurant was using or if that's still a thing now. We couldn't clock out until we claimed atleast 10% of our total sales... Now with so much more credit card usage, I'm sure it's easier to accurately track how much servers should be claiming.