Right now, many people who work in the food service sector make a wage far below minimum wage due to laws that allow mainly the restaurant industry to underpay their workers based on an assumption that everyone will tip.
A livable wage is a human right. Even the Federal minimum wage isn't livable, and restaurant staff are asked to live on a wage much lower than that.
This also provides a false representation of cost to consumers, which is, essentially, false advertising. If I went into a store to purchase a garment and then was told that I would have to pay 20% more than the price on the tag, the store would be in serious trouble, but restaurants get away with this all the time. It would be better if prices at restaurants would increased by 20% and the staff were paid a fair wage.