kelly, I'm averse to 'it's late, I'm tired' when used as a throw away line with no consideration given as to the strategies to mitigate it. I'm averse to the 'strategy' articulated being stuff that should be done all the time. I'd be much more impressed if the person said 'I'm tired and so I'll possibly make some errors' which is the type of sharing information that I like. I'd be even more impressed if they mentioned that well before the departure or arrival briefing. I suggest that if that's the first time it's rated a mention then it's been managed quite INappropriately. It should have been discussed and managed much earlier. If it was dealt with earlier then why do we need to flog ourselves with it yet again?
If a guy mentions Terrain as a risk, I am sure you could use the same arguement of "what should we do differently".
'Terrain is a threat, there is no weather, can you go to terrain switch now'.
'Terrain is a threat, there is some weather around, can you go to terrain switch at 10'000 feet'.
'Terrain is a threat, there is heaps of weather around, can you go to terrain when we're cleared to a level below LSALT'.
Somehow I think that they're further apart than you think.
Still, rather than get caught in semantics, let's go back to first principles. Threats are things that require crew management and are external to the crew. Errors are things the crew stuffs up.