Incredible. I don't know what kind of story they used to talk themselves into the building, but it must have been a good one. Of course, the big issue is that President Obama could have been at great risk if they had meant to do him harm. While it is true attendees had to go through metal detectors to get in, it doesn't mean that they couldn't have used something like anthrax to hurt him.
However, there is no evidence at all that they meant ill will. It appears nothing more than a publicity stunt for them. Mrs. Salahi is apparently in the hunt to appear on a reality television show (big surprise, right?). If the goal was publicity, they succeeded.
Still, this makes me very uneasy regarding the president's security. If something like this can happen, the Secret Service needs to re-think its policies and procedures. And fast.