In HS, I washed dishes in a restaurant in my hometown. The waiters (all white, young attractive 20 somethings) would _occasionally_ share out a few dollars of tips to us on a very busy night. The dishwashers were highschool students immigrants. The work for dishwashers naturally scales linearly with the number of orders.
Certainly I think it's BS that as a customer, I'm not sure whether the management is just taking these (and telling their workers "oh, you're getting minimum wage; you don't need tips"). But if we're gonna be tipping for _every_ service, should the person that takes your coffee order get the whole tip, rather than the person who's making drinks, or doing prep work in the back?
I have a feeling the answer is yes, or don't know, and if there were any regulation enacted the best would be to ensure gratuities before service provided are either banned or guaranteed to be hidden. Gratuities after service provided don't seem to require any restriction.
Disclaimer: I live in a country without tips and love it, would feel better on trips to the US if it were the same.