I’m pretty sure the so called sauna suits were “technically against the rules” even back in the 70’s when “everybody” was doing it. (Or so I was told at the time.) However, it was most generally overlooked kind of like driving a few miles over the speed limit. I think at least a lot of schools were openly handing them out as standard practice equipment. And I think they must have been recognized as being POTENTIALLY dangerous even then or they probably wouldn’t have already been “technically against the rules”. However, I think enforcement became more of a priority after some tragic events occurred (as has already been pointed out). Of course, those tragic events were brought on by some very severe and extreme abuses.
Certainly, use of sauna suits can be potentially dangerous as are many rapid weight loss techniques. Sauna suits are against the rules and so should not be used. But if we are talking about potential risk and endangerment and not just about breaking rules, any method of losing large amount of weight rapidly through dehydration is fraught with equal risk. For certain, to be losing 10 pounds via dehydration in a week (or even weekly?) certainly isn’t healthy and can cause not only short term but long term health risks. So if we are castigating Carmel wrestling for breaking rules, okay. But if we are tsk-tsk-ing them for potentially endangering the wrestlers, I think perhaps a lot of people better be wary of their own glass houses.