Speaking to a guy with an 1D Mk III at Oulton Park on Saturday who had been shooting the previous day in very wet conditions and rain had seeped through into the view finder. He had tried unsuccessfully to dry it out overnight and was suffering bad condensation on the Saturday. I know it was very wet but thought the seal on a professional camera would have prevented this from happening, so a bit disappointed.
Good news, he had not reported any focussing problems, well maybe a little bit! No worse than his Mk II.