I do love this sort of story and although it is extreme that some mongs have driven over a cliff, my Quest (even with off road turned off) has a tenuous grip on reality.
I planned "windmills" route for the Bishops Finger bunkhouse weekend in November. We never really got to grips with much of it as it was cold and icy.
I did it again on Sunday with soem mates from the Suzuki OC and the BMF in Kent. The route it took us was on tarmac, although the amount of tarmac was debatable and most of it, after three days of heavy rain, was covered in mud and tree debris.. But "Doris" never swayed off her route; Stelling Minnis to Barham via woodland roads including a 28% grade uphill climb. No probs for the GS, but the 1200RT and Blackbirds weren't very happy.... Shame I couldn't stop to take few scenic pics.
But the Quest has taken me to many places I wouldn't even think about if I just had to look at the map, and once there, with few exceptions, it gets me back to where I want to be.
Exceptions being central Paris where it constantly lost the signal.... and the City of London when trying to find an address!
For a bloke that likes to read maps and plan my trips, here and abroad, it is a great toy.