Assuming Aunt Leslie told all of her kids to pack their own suitcases, I imagine Fuller’s bringing a lot of Pepsi to France.
She should know better.
In the first movie, Kevin’s Aunt Leslie scoots Kevin off to go pack his suitcase, as though this is something a kid should have any business doing ahead of an international family vacation.
Now, if Aunt Leslie were an adult with no experience with young children, we might give her ridiculous order a pass, but she has five of her own.