"Satnavs should not be relied upon,..."
And that is precisely why the use of them should be part of the test. If you end up blindly following the satnav without any thought to where "Turn Left!" is going to send you, then you should fail.
Disclaimer: I do use a Satnav on some journeys, though it is a family game to yell "No!" at the Satnav when we decide that isn't the way we are going - which is more often than not.