I was a fairly early adopter of GPS in aviation, along with two friends I bought one of the first Trimble GPS units in Australia- $AU10,000 if you please, it was the size of two encyclopedias ran on either a cigarette lighter socket or (from memory and may be exaggerating) around 30 AA batteries (for not very long). It was a tremendous navigation aid, but at the time could not be relied upon due to SA. Never the less on a black moonless night in the middle of the GAFA (Great Australian F'all) it was a comfort to have your dead reckoning and the few fixes from radio aids backed up.
To my great annoyance as GPS became cheaper (rapidly) and smaller, more and more pilots came to rely on the things to the detriment of their navigation skills. I was once tasked to go with a young pilot doing his last solo nav-exes prior to obtaining a commercial licence. Little did I realize that his instructor had set him up with me for a very particular reason.
The particular exercise involved a night flight from Townsville to the old mining town of Chillagoe, from there to another old mining town of Charters Towers and then home to Townsville.
Although I was not flying in command I familiarised myself with the planned route and spent some time looking at the map and thinking about what I would expect to see on the ground. As it happened the route (as was cunningly planned by the instructor) passed over or very near to a large number of things that would be viable, even at night - stuff like big lakes, islands, small towns etc.
About 35 minutes after we left it was full dark and I noticed that the pilot flying was watching his GPS constantly and had not once put his eyes out of the aeroplane to match the planned course to what was on the ground.
I reached over, turned off the GPS and took the batteries out and put them in my pocket. After a couple of minutes when t was obvious that he was all at sea I offered to take over whilst he oriented himself to the ground and worked out what he should be seeing going forward.
After handing back the aeroplane he did OK, but it was obvious he had become overly dependant on his GPS.
Not much was said in the plane but during his debrief the next day I heard that he had told the instructor that I wa sa complete bastard and that I had taken his GPS batteries out and made him navigate using radio aids and ground features.
The instructor's comment - "I thought Tony might do something like that and if you learn the lesson, he has probably saved your life one day."
I felt that I'd paid something forward as I was trained to instrument navigate by a former Mosquito pathfinder navigator. Mr Sugar saved my life quite a few times.