In the years since the Cold War, the threat of imminent global thermonuclear war has receded in the popular imagination. Computer hackers are buying up abandoned missile silos. It’s been almost a decade since a major Hollywood film revolved around a U.S.-Russian nuclear exchange. But that doesn’t mean deterrence has succeeded in finally staving off nuclear war. Stanford University Professor Emeritus Martin Hellman, comparing his love of gliders with his interest in nuclear deterrence, wants to remind you that when a system is 99.9 percent safe but the remaining 0.1 percent contains an absolutely catastrophic outcome, it’s not a great system. Sound familiar? [%comments]

I agree with #5, Traciatim – reality kinda limits us to less than 100%, so too bad.
ahh pot odds and Taleb…yes
Problem with the 1%, or even .1%, is that the outcome is not actually catastrophic and people tend to round .000000000000000000000001 up to 1%.