It would be irresponsible to take any but the smallest boat out without GPS, now that it is available. But to solely rely on it for navigation is suicidal.

I use GPS to get a fix, but I lay out my DR track and confirm my electronic readings with traditional methods, not just for backup, but to keep my skills sharp in case I lose the GPS, or for whatever reason, lose confidence in what its telling me.

The problem isn't just the possibility of malfunction, GPS is pretty reliable, but you can't develop the situational awareness you need to handle confusion and emergencies if you spend all your time mastering a GUI. Sometimes you just have to look out the bridge windows.

The situation is analogous to the introduction of navigational radar on ships. It did little to prevent collisions, even in perfect conditions. People relied on the black box and then forgot to take the most elementary precautions.