Some family will depend on you forgetting to ask for payment, when they show up at the door. It's a tradition for them. I have one that showed up, paid at the picnic grounds, got the 1st full plate of everything put it in the car, came back went through the line again and got another full plate ate this one, then went back and got another full plate of whatever was available, and went home. They didn't bat an eye when we all looked at them. The comment after picnic was, I was going to get my money's worth. Needless to say when we have anything to do with celebrating and food is included a lot of times this person is not invited and they just don't understand why. Family can hurt you worse than a stranger. Have fun anyway.