I'm getting this critical error when I run the Pre-Deployment Analyzer for Exchange 2010: Permissions inheritance block on OU. It says this *may* cause mail flow problems, recipient update service failures, and other service outages. I know how to fix it. What I'm wondering is why is this a problem? Under what circumstances would I experience mailflow problems, recipient update service failures and other service outages? Everything I read about it online is very vague. Can anyone give me a specific scenario under which this might occur?