The only way to stop a false-flag attack, either at the Olympics or the Superbowl, is to create a public climate in which the planners of suich a false-flag start to worry if the cover story will be believed.
Especially in the wake of 9-11, Saddam's "nooks", Climategate, swine-gate, etc. etc. etc. the US government has to understand that they have lost the faith and trust of the people. It is no longer a slam dunk that the American people will accept what the government tells them at face value. They have to wonder if they might not be believed the next time.
If we can shake their confidence, if we can make them doubt, they will have to call it off.