I see no point in these national threat level for the general public. It's basically the gov saying "you should be more afraid!!!"
It is kind of pointless. But they damned if they do damned if they don't.
*terrorist incident happens without warning*
Public: WTH? OMG! Why was we not warned?
Government/ Secret Service: We didn't know anything..
Public: OMFG! WHAT DO YOU GUYS DO?!?!?! USELESS!!!
*terrorist incident happens without warning*
Public: WTH? OMG! Why was we not warned?
Government/ Secret Service: We didn't want to scare you...
Public: OMFG! CAN'T KEEP THAT STUFF FROM US!!!! USELESS!!!
*Warning increases and terrorsit incident*
Public: WTH? OMG! Why were they not stopped?
Government/ Secret Service: Intelligence was lacking...
Public: BUT YOU KNEW SOMETHING WAS GOING TO HAPPEN!! USELESS!!!
*Warning increases but no incident*
Public: WTH? MORE SCAREMONGERING!! Just arrest them!!! WHAT DO YOU DO ALL DAY?!?!
Government/ Secret Service: Sigh...