Noakes is an evangelist, to be sure, and I think he often overstates his case and perhaps evangelizes to the detriment of his cause. I do not necessarily see a great conspiracy of manufacturers to misinform. Nor do I think the ACSM made up it's hydration guidelines (which are changing to be more "Noakesist", as I understand it) based on influence from the supplement industry. All that said...
I disagree with your assertion that there are as many "Non-Noakesians" at this point as there are "Noakesians". Even in the purely clinical setting (which usually lags the research world by a fair measure), there were nephrologists saying the same sorts of things before Noakes really got any steam behind him. At the end of the day, exercise induced hyponatremia fulfills the major diagnostic criteria of SIADH, the primary treatment of which is water restriction. Is it possible to have hyponatremia in the settings of euvolemia, hypovolemia, and hypervolemia, yes. However, the euvolemic and hypovolemic varieties are not typically seen in the endurance sports arena. Some of us were talking this over at the latest ACSM meeting...none of us could recall a case of hyponatremia in an endurance athlete that was anything other than hypervolemic.
I can't say too much about the "Non-Noakesians" at this point, simply because their viewpoint is not well represented in the literature. I can say that most of the sports physicians I have worked with who were "Non-Noakesians" were of that ilk because they were unaware of recent publications, and because they live and die by documents such as the ACSM's guidelines, rather than the primary literature.
Is it as simple as voluntary "overdrinking"? Maybe, maybe not, at least not in all cases. People with SIADH are driven to drink, and I do not think such a phenomena is outside the realm of possibility in endurance athletes. However, as far as I know no one has demonstrated such a drive in endurance athletes, or formally investigated the motivation of the athletes to drink quite so much. I suspect it might go beyond that they got poor hydration advice ("drink as much as you can".) I can say that in the cases where I have played a major role in treatment (around a dozen, all told, some worse than others), I have only heard variations of one explanation. "I was feeling bad, and I thought I must be dehydrated, so I drank more." All patients had had a significant weight gain, which can mean only one thing: a positive fluid balance.
Are there other viewpoints, sure. However, the people who believe hyponatremia is due to electrolyte loss don't have much data to stand on. The people who believe it can be corrected through the administration of oral electrolyte preparations are lacking data as well.
At this point, I think it is pretty hard to argue with the overdrinking argument. I think there is more to be learned about the actual mechanism, but at the end of the day, the treatment may well be the same.
Dr. Philip Skiba
PhysFarm Training Systems
Coaching and Consulting for World Champions, and You.