I have seen it several times now... I know damn well we backed them off an attack of Iran in 2007 / 2008. Getting called out on a plot leaves them vulnerable to exposure, they will cancel a plan and wait for another day to keep their game afloat.
Did you know that UK cops got filmed planting bombs around the city? I think they fully intended to attack the Olympics, but got caught in the preparation phase and so put it off. And I think ANY mass gathering is a dangerous place to be these days. You could give me front row 50 yard line tickets and I would not go. Will they attack? YES. Will it be at THIS event? Maybe, maybe not.
This is the article that got my posting privileges revoked: