Allowing Local Administrators to Bypass Managed Client (MCX) Settings in Lion
In earlier flavors of OS X Server, when a local administrator logged into a machine that had managed settings applied, they were asked if they wanted those settings applied to that session, via the following dialog:
If you chose to remember your choice, you could just hold the option key the next time you logged in, and you would be able to choose again.
Unfortunately, I couldn't get that working in Lion. With 10.7.4 Server and clients, no matter what I did, the dialog would not come up, and managed settings were continuously applied.
After digging around, I worked out that by applying the following two keys to com.apple.loginwindow, I regained access to this feature:
AdminMayDisableMCX = TRUE
LocalUsersHaveWorkgroups = TRUE
You can see what that looks like in Workgroup Manager here: