What about asking the parents to supply an extra bottle of milk that you can give to the child. Many of my parents have a cup of juice in the car for the child and many have a snack the child gets for the ride home - even those that live only a few blocks away. Child has come to expect it and will ask for it even while dressing to go home like I didn't feed them all day as if they will fade into oblivion if they don't "finally" get some more food. It just makes me laugh most days and parents don't seem to question my meals. I will sometimes if a child is being over dramatic make a comment mentioning how recent snack was. The key here is if the child is to have an "extra" snack it needs to be provided by the parent because they have received the meal and two snacks they paid for. I think the rudest one is when the parent would ask me to fill a bottle or cup for the trip home cause the kid is hungry. That is where the juice in the car comes from. If I fill the bottle it is with water to combat thirst as that is more often the need since we were just playing.