I remember as a brand new navigator doing a low level course on JPs we were transiting to a low level area (remember them?) and pointing out to my pilot that he had descended below safety altitude in IMC. The situation was not remotely as dangerous as the events which are being discussed in this thread. The pilot, a very experienced and respected QFI immediately thanked me for pointing out his error and climbed back above safety altitude. Not everyone in his position would have taken kindly to being corrected by a sprog navigator, but its the difference between a professional pilot and a cowboy in my book.