I've seen a few examples on youtube of people following the GPS to their own peril ( the last one being, driving in the sea directly)

However, the confusion i think comes from the fact that GPS is 99% of the time better than you at picking the correct road to reach a destination.

The problem with all those systems is that they're better than you 99% of the time, and they fail miserably in that last 1%. Makes it totally unsuitable for anything of importance i think ( same reason why GPS is fine, yet automatic driving isn't there yet).