I don't think that's cheating. They are just using information that is there for everyone. But that's not really a game, is it? Rather hard work <img src="/ubbthreads/images/graemlins/ouch.gif" alt="" />
I usually don't exploit bugs in a game, since I always play single player games. I feel this is cheating in a way as it is just a mistake the programmers made. It's not in the sense of the game and it would destroy the atmosphere.
My morale in this matter is a bit strange though. So what I sometimes do is use a cheat to achieve something which I feel I deserve but can't get in an honest way. As an example in Gothic I inserted one of the swords which I had found but somehow lost. When I couldn't find it I cheated instead of reloading and replaying some hours.