This salad dressing is expired but I am going to serve it anyways.
How would you be able to serve it without people knowing they're eating expired salad dressing?
Nobody will notice the expiration date if the salad dressing is on.
Serving expired food can make people very sick. You should not  serve it to them, you could hurt someone.
Most customers don't even order the salad.
It doesn't matter how many eat it. You shouldn't serve expired food, because that's wrong and could make someone sick.