So I have a Corsair 4000D air flow, and the top of the case is like full of holes to allow airflow (with a dust filter on top of it).
Thing is, I put the case more or less below where my hand is touching the mouse, to the right of my feet.
And, well, I could wash my hands or otherwise have my hands be slightly wet at some point, so I am afraid, those holes would be easy for a drop or two of water to fall down on the PC components.
A couple of water drops falling somewhere in your case have a very small chance of frying the thing. A drop would have to precisely hit a live pin somewhere, I think chances of that are slim.
But yeah, as was asked before, I wonder how often you would use your pc with fully wet hands. Maybe dry your hands on a towel after washing them.