Imagine a major trial in which evidence is given by a judge. The judge, as witness, has nothing to gain and has nothing at risk. The judge is testifying about something he knew about and affected him personally.
Would you accept the judge's testimony?
Of course - the judge wouldn't lie.
But the judge got it wrong.
It seems that recent testimony by Marc Nadon about his possible career is hockey was just wrong. And wrong in material ways.
It's pretty clear that Justice Nadon didn't lie -- he told the true as he remembered it. But he was wrong.
Now the reason to comment isn't to say Justice Nadon is not fit to be a judge - I haven't dealt with him but second hand reports say he is competent and bright.
The point is if a judge can have a memory lapse about something that happened to him, consider the risk of error for an ordinary witness.
Take all evidence with a grain of salt!