Reminds me of an old anecdote about the frequent flyer who started to obsess that a fellow passenger might be a bomb wielding terrorists, so he consulted a statistician for reassurance.
The Statistician calculated that the odds of him getting on a plane with someone carrying a bomb at about ten thousand to one.
However, this did not reassure our frequent flyer at all, in fact it worried him greatly, so he asked how the risk might be mitigated.
The Statistician thought for a moment and then declared "Take a bomb on-board yourself! The odds of there being two bombers are almost negligible."