I would also walk from this one, or tell them the only way is to do it all. Your reputation and liability is worth walking away. If they say no, part in good terms. If they say yes, then you hold your own destinay and reputation in your own hands.
You can cut down a million trees and never be called a lumberjack, but make one bad catering job because of the Customer not supplying something, and you are a chitty cateror the rest of your life ... to all 3 shifts of people depending on you.
Big Jim - Newnan, GA
Customized Lang Model 84 Longneck