I always thought that keeping secrets in this day and age of 24 hour cable and a -if-they're-not-traitors-what-more-could-they-do-to-be-traitors? Media is virtually impossible, especially with troop movements...
Just like Somalian boys with cell phones alerting their bosses that birds were enroute, I don't see how any modern and massive force can be brought to bear without a modern nation knowing they're coming... everything from knowing the approximate flying time from MO to Iran for a B-2 and then simply posting someone within earshot of the runways.... to using open source sat photos of the Gulf region (or Russian spy sats).
If we ever do invade Iran it'll have to be something fast and furious or they'll not only see them coming but be ready. Worse, chances are always high some media type, congressional staffer, or other dim bulb will blab the whole thing to the press 24 hours ahead of time.