i did once and it didn't go so well. there was moisture on it which kinda ruined the picture a bit.
I had no problems at all.
I've done it w/o problems.
The best way is to box the cake, then put that into a plastic bag. When you take it out, don't remove it from the wrapping at all until it has reached room temp.
It will depend on how humid it is in your area. I've done it in both a very dry area and in humid place.