Sounds like the conversations I had with people every winter when I was working at Factory Card Outlet.

"Your mylar balloon will shrink when you bring it outside. As soon as you bring it inside, and it warms up, it will be fine."

Customer goes outside, balloon shrinks and starts to fall, customer comes back to the store to complain. I finish dealing with whatever, and walk slowly over to them, and repeat, pointing to the balloon, which is warming and filling as I speak...