In my combatives classes, I run drills that are designed to produce excessive stress and sensory/neural overrides in order to deal with this issue. You cannot sustain training by training this way all the time, but it is a very important part of training if you are training for real.
I've done a little such training and it was very valuable to educate me on the effects of adrenaline on my mind and body and how to deal with it. But in my previous post I was talking more about the effects of fear than the effects of adrenaline (although I recognize that there's an overlap).
As to David Skagg's questions, I suppose one could determine from practice in the dojo that the student would be effective in a fight, yet at the same time determine that the student's attempts to apply aikido during that fight (whether it's aikido techniques or simply aikido principles) would be ineffective.
As for George Ledyard's posts, I agree with and appreciate everything he's written here. Thanks, George.