I've never sprayed water directly on shelves, I've only seasoned them like a small humidor with distilled water. I put them in an airtight area with a shot glass (or more) of distilled water. I'll let someone more knowledgable answer, but for me personally I was always worried about too much water being absorbed and the wood warping or swelling too much to where there isn't a good fit.
Again, I'm sure someone with more knowledge will post
