the first provable publicity that the agent gave this event was the news conference which happened after American Airlines put material on their website which the agent felt to be untrue and which pictured him in a poor light.
Given the scene of an armed arab-American claiming to be a secret service agent at the gate arguing with pilot and gate personnel with cop standing by, do you really think that the agent had to be the person who leaked the story to the press. There could have been hundreds of people that could have observed this. Recall the Agents coat was on the plane. The airline refused to let him reboard to get it or bring it to him. As a consequence, he's standing there with shoulder holster clearly visible. You think that didnt attract some attention among the Christmas travelers?