When people are accused of engaging in elaborate plots, commentators frequently dismiss the accusations by citing Occam's Razor. "Don't you realize how many people would have to be involved?"
They're not wrong to ask this. But this isn't the only way Occam's Razor can be applied.
In Lance Armstrong's case, you could point to this very simple explanation: when someone outperforms in his sport so overwhelmingly--especially post-cancer--it is not unreasonable to suspect complex cheating. Another simple explanation: when major bucks (Libor scandal) are on the line, it is not unreasonable to expect that people will go to very elaborate (quiz show scandal) lengths--involving multiple actors--to accomplish this cheating.
Incredible outperformance of the sort Lance Armstrong (or Bernie Madoff) demonstrated could lead you back to this always simple explanation: If something seems too good to be true, it probably is.