5 sigma is kind of arbitrary, isn't it? Just a nice "round" number. Obviously better than 4.9, but the line is fuzzy, if it even exists.

Correct. What really counts is independent verification, all at high sigmas: Tevatron, CMS, Atlas.

But then at the end he kept mis-speaking as to whether there were five Directors-General or six. Maybe they're at 5.9 sigma after all!

could you explain in easy terms what getting to 5 would mean? thanks

I am just a hobbyist, but as i understand it, 5.0 sigma is just the probability of the result being bogus. So 5 sigma is very high probability, something like one in 1.4 million. i.e. the chances of the result being wrong is one in 1.4 mil. 4.9 sigma will mean lesser probability, but i am not sure by exactly how much will that 1.4 mil number reduce.