Have you ever taken a philosophy class? The things that you really know for sure are very, very limited ... "I think, therefore, I am" is about all you really know.
Even if you are on a jury, and you are presented with what seems to be overwhelming evidence - you simply don't know for sure. It could simply be some made up evidence.
If you do not have a reasonable suspicion about things in general, then you are naive. Look at ol' Marion Jones and Jacobs - people were sounding the alarm long before they were busted. Even the head of the IOC said to the press, paraphrase "Miss Jones would do well to choose her associates more wisely" - nice.
The Goucher's have forever tainted their reputation by associating with Salazar. What do you make of Galen Rupp, the hypothyroid asthmatic? What are the chances of that? Imagine how good he would be if he were not a hypothyroid asthmatic and didn't have to take all of those drugs.