Originally Posted by The_Sugar_Fairy
...(1) refrigerating causes condensation beads (when the cake returns to room temperature) under the buttercream or fondant...
That's not possible. A cake cannot sweat under frosting.
Science lesson: Cakes do not sweat. Any moisture you see on the outside of a cake, frosted or otherwise, is not moisture coming from the cake...or from the fridge. It is the humidity in the warm air outside of your fridge, condensing on your cold cake when you take it out.
So, the humidity in the air can condense on your frosting or fondant. But it can't travel through frosting to get underneath it on your cake.
Water takes different forms depending on its temperature, from steam/humidity at the warm end, liquid in the middle range to solid/ice at the cold end.
When the humidity (warm/gas) in the air in your room hits the cool of your cake, the temperature changes the gas to a liquid which accumulates on the cool cake surface.
So, the cure for decorated cakes sweating when you take them out of the fridge is to prevent the humid air from getting to your cake. If the cake is in a box when you take it out, the humid/warm/gas cannot reach the cool surface of the cake. It will hit the outside of the cool box and condense there, leaving your cake surface perfectly dry. The cake will be safe as it comes to room temp.
So, if your cake is already frosted or fondanted, the frosting actually acts as a barrier (just like the box does), preventing the humidity from getting to the cake underneath. So, when you take a frosted cake out of the fridge, condensation will only accumulate on the outside surface of the frosting, not, beneath it, between it and the cake.