Should waiters/ waitresses be required to stay home when sick and still have symptoms?

So me and my husband brought his grandma out to eat at a restaurant. Our waitress came and took our drink orders and it was clear she was sneezing, sniffling, and coughing. While taking my grandmas drink order the waitress started coughing and then apologized saying she is just getting over a cold. My grandma who owned 3 restaurants before she retired straight up told her she shouldn’t have come to work and she has sent her employees home for trying to come to work sick. My grandma then told her we are going to eat at a different restaurant and she can’t risk catching something at her age.

This can be complicated because cold symptoms can last for weeks and not be contagious even though you still have symptoms. I believe I’ve heard your actually most contagious before you even get symptoms that your sick. If waiters / waitresses have obvious cold symptoms like this lady should they be turned away to not work?