You're absolutely right, but because I used to work with the parents, I felt a little weird about the whole contract signing. We have a contract, but it doesn't specify minimum numbers only the payment schedule. On the other hand, I thought they'd be honest enough not to try to get something for nothing. Too late now, but I guess I'll contact her and tell her what my normal policy is.
Another oddity about this wedding is that we set out the payment schedule requiring that they pay 25% up front, and three more equal payments, the final one due one week prior to the wedding. The bride brought in 25% of what the first payment should have been-$375 as opposed to $1500. Her father contacted me and told me that she had no idea how much her food/catering should cost. I've since heard through the grapevine that the grandparents have asked around at area restaurants to see if I was ripping her off. Luckily, my friend, who owns one of the restauants called me to give me a heads up.
They are getting the deal of the century at $21.95 plus tax and service for 4 entrees including chicken, beef, crab stuffed sole, and pasta; 4 sides, 4 apps including shrimp cocktail. Total bill was to be around $6K for 200 people.
She may be a bit*h, but I am a sucker. I'm going to keep thinking about last weekend's wedding where the bride and the mother of the groom hugged me because they were so happy with everything. They had the photographer come into the food prep tent and take a picture of my crew and myself at the couple's request. The groom even came into the shop and tipped me $500 a couple of days after.
I can bet the farm that I won't be getting any kind of tip this Saturday....

I think I'll be chasing them for the final couple of hundred dollars for months to come.