CBFO,
In my view everybody who is advocating guns on the flight deck or is prepared to give it a go, is guilty of allowing the government of the USA to get away with crap security at airports "because they have provided for extra security on board". That is why I used the term 'fanatics", because of the very limited scope of the discussion.
And yes, there will be a number of responsible adults with gun handling experience among the pilots, but it still is an accident waiting to happen. The pilot is the least capable person on board to handle a gunfight as far as position and location is concerned.
OTOH, an SAS trooper facing rearwards, now we're talking..
And Tenke, I agree wholehartedly. That is why I will resign from my chosen occupation should a similar system be adopted in my company (not very likely, though).