Having worked in a bistro kitchen, I can tell you what happens when you do this and it's not the waiters getting fired. LOL.
fesshole 🧻I tell waiters what I think of a dish, even when it's bad. My husband says this is wrong and I must stop. But if I don't tell them that their sauce is watery or a medium rare steak is actually well done then they'll never improve and they all lose their jobs. Honesty is polite.