Sugar is an incredible preservative! Check your ph level on fillings and icings. You'll be surprised how many (other than creams) do not need refrigeration. Yes, how fondant reacts totally has to do with humidity, in the refrigeration unit you are using. Here in Florida, I rarely put fondant in the fridge. Since all my cakes will be eaten within 3 days, I use many fresh fillings and icings, but no cream. Again, check your ph level. I would die to have Duffs walk in! BTW, according to Colette Peters, she never puts a fondant cake in the refrigerator. No need, everything has sugar in it.