I hadn't checked in a long time.. I can't believe this is still going on.
I got my 5D Mk I the first month they came out.. it has been rained on MANY times and has never missed a blink. It's been exposed to sea spray, I've hiked through ridiculous humidity in Hawaii with it, etc..
I just got back from a week in California with it.. it got wet several times. I don't even really think about it.. I let it get a little wet and have zero worries.
Hopefully the 5D Mk III I will eventually buy will be more like the Mk I then the Mk II.