Have there ever been considered to use some kind of visual cue (a la <style> <class name="devel"/> </style> in the .ui files) to be aware you are in a administrative tab (apart from the “administrator root” title in the navigation bar) ?
GNOME console already switches style when switching to root user. So, I think this topic might be of interest to the GNOME HIG team. Something like the following might be a HIG guideline:
If the app can operate in multiple privilege levels, the app should visually differentiate each level in the UI.