[Sombre]

And if you don't want to test something or can't test it, don't present what you believe as fact.

Too many times I have seen people quoting the manual as evidence that they are right about something, or simply saying "X works in Y way and never Z" without qualifying it. When I believe something from playing the game but haven't tested it, I will generally say something along the lines of "I am 80% sure of X and people seem to concur, but in order to be sure this requires a test".