Sept 11 all over again?

(photo taken from Jason McLane's camera phone in New York City)

It came as a shock to many New Yorkers when they looked up to the sky and saw a low flying plane which looked like Air Force One being followed closely by an F-16 bomber. It shocked people to the point that 911 call centers were jammed with calls, all thinking they were experiencing another terrorist attack. Sure, it has been almost 8 years since the fateful incident, but its not something that is going to be easily erased from one's memory and what else were the people to think was happening?
Come to find out this was not a terrorist attack. It was actually staged by the US government as an artistic photo opportunity. They wanted pictures of Air Force One being chased by a F-16 with the New York City scape and the Statue of Liberty in the background. Naturally something as public as this was surely going to draw a lot of attention, but New York City officials were specifically told to not inform the general public. This leads me to ask the question: Why?

Why would you not tell the public?
Why would you risk causing mass panic through out the city and possibly the country?
Why would you spend $300K+ to charter the two aircraft during a recession?

Its almost as bad as telling everyone in the city to not ride the subway because if they do they would most certainly die of Swine Flu...

(More here)