Originally posted by CarMan It will cover the shutter button as well!
I don't see how that would hamper use. As long as the pressure on the shutter is not enough to trigger the half press mode you should be able to press down to get it to fire but leave it alone at other times.
As for a shield another method would be to find a material that was thin enough to slip into the slot above and below the wheel say polystyrene from a discarded package - and bend a small u shaped piece - cut a slot in it for the place where the wheel is supported and it might just fit in there reasonably well. It could damage or diminish water seals depending on how they are implemented in that area of the body however.
I still think a wired remote is a reasonsble answer - it keeps your fingers away from the shutter/wheel area. You can tape it to the side of the tripod or put it in your pocket or clip to your pants/shirt etc.