There have been a few blades offered on the sale thread where rust was bubbling up from beneath the undamaged coating. The coating greatly reduces the risk of rust but looks like it doesn't eliminate it. I give all my coated blades a good Ballistol rubdown when new and after hard or wet use. I figure it doesn't hurt to seal any potential pores in the coating.
In any case, I would think the amount of rust with the coating under the scales would be very insignificant if even possible (unless immersed in a saltwater bog beside a toxic waste dump in the rain).