It would appear that I seem to have stirred up a hornets nest with this one. As always I only ask questions which I believe are pertinent to my understanding of the rules and hence my enjoyment of the hobby.
I tend to agree with swampsters point about terrain and positioning of commanders, etc. The whole point of intervening terrain should be considered irrelevant, I presume the rules are trying to simulate(very well) the following circumstances:
The CinC is personally delivering the bigade order changes (i.e. in game terms base to base contact with GdeB) and as such the CinC is in a more vulnerable position.
Or the CinC has sent a messenger to deliver the brigade order changes (i.e. in game terms not in base to base contact with GdeB), and the CinC should be in a less hazardous position.
I would suggest that if the situation I outlined at the start of this thread occurs again that the highest ranking commander is always considered at risk under the loss to general table. (It wouldn't always result in his loss though). That way, people will take more care over how and where they position their commanders.