I agree. Mo Farah I believe personally will be outed in 5-10 years time when the testing improves again and his historical samples are re-tested. He has a history of missed drug tests and he would be the ONLY member of his training group in the USA that has never been popped for PED's.
I love to believe in exceptions but this smacks of the Armstrong case all over again. When something walks like duck, quacks like duck - it's usually a duck.
I can just about believe Bolt because he's been a genetic freak like Phelps since he was 15. However his country have an appalling record of testing athetes and if you look at a chart of the 15 fastest 100 metre times of history by different individuals - Bolt is the only one who has never been popped for PED's
So it will be interesting to see over the coming years . As Rio has been a shambles of an Olympics from top to bottom in terms of samples not being tested and still not yet tested.