‘It put everyone in a weird position’: Our waitress said a 20% service fee was added to cover benefits and health insurance, but that it was not a tip. Is this normal?

Dear Moneyist,

I went to brunch last weekend and, when the server handed us the bill, she said a 20% service fee was added to cover her benefits and health insurance, but that it was not a tip. 

I am absolutely supportive of paying restaurant and waitstaff a living wage and they deserve to have benefits. But I wish…