For the three instances that you referenced, those are allegations. I would not expect any AO to take action about allegations seen on the internet. As others have said there are always cheating allegations, tests being stolen/leaked and the like.
I read apps and do typically google Regeneron ISEF and other top award winners, and allegations likely wouldn’t impact an app. OTOH, if a winner at that level were ultimately to lose their award I would expect there could be consequences at some schools, e.g., rescind admission, maybe even expel someone if it happened a year or two later (I would expect that would be highly variable across schools and depend on the nature of the situation.)