I always take an empty bottle with me and get water from a water fountain in the security area.
I have had empty bottles taken away from me in the secured area of airports. I asked what possible harm they thought I could do with a bottle that went through security empty and I was only going to fill within the secured area. They said "policy."
Civilization is fast devolving into Idiocracy.
I also feel like anyone around the kid could have taken the $5 and just charged the blanket for them. Not only did the airlines not help out but no one did. I bet no one was ever asked to help out.