When you configure folder redirection on my documents in group policy and check the "Grant exclusive rights" check box, only the SYSTEM and user has rights to the folder. Domain administrators loose accesss.
I know how to manually add access back by changing the permissions/ownership but I'm sure I read about an additional group policy setting that modifies this mechanism so that administrators are also included when a workstation takes over exclusive control.
But I can't for the life of me find any details about what the policy is called/where it is. First time in a while that Google has let me down.