Why do you say that?
I know the 5D isn't sealed as well as a 1 series but it shouldn't have any issues with rain. I'm convinced after watching the digitalrev 5d2 vs 7d video a while back. I shot in the rain with my 40D before as well with no problems.
I agree. Couple weeks ago shot in a little hail/blizzard/freezing rain and was more worried about the lens than the body. Ive shot in light rain and snow with my 5D2 and never had any issues. I think anything short of full torrential rain the 5D2 will be fine.