"I just don't want the ATO to switch it off completely since I am not "approved" to use it,"
The ATO can always just switch it off anyway to simulate a failure. Heck, I had to find a an old railway carriage in someone's backyard under a tree way out in the bush as part of my CPL test. Diversions etc and no GPS at all let alone a moving map (imagine that!). Maybe we need to start a new thread: 'loss of visual navigation skills.'
I have been in the flight levels with two of Garmin's IFR TSO'd finest both going into 'DR' mode for 10 mins or so. Watcha going to do then?
The CPL is part of the day VFR syllabus and has already been mentioned, the emphasis is on visual navigation. Navigation aids (including GPS) are supplementary but should not be needed or necessary for you to succeed.