I believe that the underlying theory is that a distressed diver will naturally rip his mask off, or get it off of his face when he comes to the surface b/c the mask is "un-natural". Frankly, I think the mask on the forehead looks really dumb, and you certainly increase your chances of losing it in the ocean.....or in a lake with zero viz (just ask my brother about the latter).gj62:I agree that it isn't the wisest distress signal, but, as it was once used that way, I can't blame a DM for being cautious and interpreting it as a possible distress situation.