I enjoyed this movie. Most of it made absolutely no sense, but it was damn exciting and it had Vic Mackey as SecDef, which is pretty cool.
As for Rachel not knowing her son was playing for the President...he wasn't supposed to until the last second. That was the purpose of the scene with the ARIA-coerced government officials approaching the band teacher towards the end about the "change in plans."
I'm more concerned that someone Capitol Police believed to be an authentic FBI agent, who was admitted into the Library of Congress when the building was locked down, claims there is a direct threat against the President and ... the police don't bother to call it in. WTF? And why the hell did they let him in in the first place?
HERO: "There's a direct threat against the president and the entire chain of succession and its going down RIGHT NOW. I'm an FBI agent. See, I have a badge and everything."
COP: "No shit? Well, we better call this in..."
HERO: "No, no. You need to just let me into the library. There's no time."
COP: "Um, I have a radio right here. I just call in POTUS 111 and SS shits a brick and evacuates the building...wait, why do you have to get into the library?"
HERO: "Cause I'm the only one who can stop the fiendish plot!"
COP: "There are hundreds of Capitol Police, Marines, Secret Service and black ops counter-assassination personnel crawling all over the Capitol Building...I'm sure any one of them could-"
HERO: "You don't GET IT! Only I can disrupt the ceremony in the most dramatic way possible, get shot, inexplicably not die and save the day...and get the girl."
COP: "Oh, well, when you put it that way..." [COP unlocks door and ushers in HERO]