This year, I celebrated my birthday at DLR. We timed our trip around Star Wars Celebration, a couple weeks after my actual birthday, but it was FOR my birthday, so I decided to get a button. They didn't ask for any kind of proof at City Hall when I picked the button up. However, later that day a cast member randomly started chatting with me and I realized he was trying to slyly check if it was REALLY my birthday. That made me laugh, of course, because it wasn't.
I don't think that's something that a CM would ever do to a kid, though. I think it was mostly because I was an adult and alone at the time. He was friendly about it, but I do wonder what he'd have said if I came right out and said, "No, it's not my birthday."