I agree, however fondant can be frozen before it is applied or used. The local bakery sells their own and freezes it and we unthaw it and use it and it is fine. I haven't tried freezing gumpaste on its own though and I do know that Wilton fondant does have a hardening agent, so on its own, this might be an issue. But I find that you cannot freeze fondant covered cakes or decorations well.
But freezing the decorations results in the moisture breaking down your hardened decorations and sliming them, for lack of a better word. Also, if you leave a buttercream iced cake with fondant decorations like roses and such and seal it in a plastic container, after about 2-3 days, the decorations will be quite slimey when you go to remove them.
Hugs Squirrely Cakes