Hello Jonny,
My first paragragh should have had a smily face after it, for some reason it didnt make it to the post, but I think you spotted the intentional irony of it.
I have no stats for the numbers of misdirections, which is why I used the word 'probably'. I doubt anyone has the stats, but there were certainly several notable incidents of mainly continental drivers relying on sat nav instructions rather than using the road signs and the evidence of their own eyes.
Several villages reported massive increases in HGV traffic when SN's became more popular, and some local authorities were trying to get the digital road data companies to modify their data or mapping engines. So there is no doubt there were Sat Nav related problems.
I do agree with you that Sat Nav's can provide a prety comprehensive service these days, and they have evolved now offering better linking between vehicle size and suitable roads, but call me a ludite, anything that needs batteries can fail, where as good old paper maps seem to have a very long battery life.
Don't get me wrong, i'm not anti Sat Nav, I do use one, and as you say it does allow you consentrate more on the driving.
I also like the ability to warn of speed limits. The other facility which I have so for not needed to use, is the ability to give a map reference to the emergency or breakdown services.
All mapping systems have one major failing, and that is they are basically out of date almost as soon as they are updated.