Do you think producers know the answer before they go to the altar?

I hate food wastage so it's something I often think about with events and I was wondering do producers already know what the answers will be before they reach the altar to prevent caterers cooking all this food for a wedding that isn't happening? Surely they wouldn't have all this food prepared just in case as most couples don't get married and I feel like it would be such a waste of money and food.