Er...
Well, I work in a DIY store.
So......
:P
besides, I would prime it and then paint with either matt/gloss,
matt is water based, and gloss is oil based. and both can be used on mdf.
so yes, it can get wet, it can't be constantly wet though, or it will break up, plus it wouldn't get wet anyways, only way it could would be if i threw water all over the show, which is something I wouldn't do

I think your thinking of ply,
There are 3 types of ply wood, ply, external ply, and water ply.
Ply can't get wet, or the whole sheet if fecked, external ply can take a certain amount of water, but cant be submerged, an water ply is completely water proof.
Anyways, thanks for the warning!