Keywords can be dangerous things.

I was just wondering - if he'd said 'Well, that joke about the Taliban really bombed - off to get the plane now', would the same systems have picked it up? Or 'Can you send me the blow-up of that Taliban photo to look at on the plane?'.

Presumably they don't just base it on which words crop up - which means someone is actually analysing the intercepted messages for credibility, right?