If this is legitimate intel, I'd bet there is a hell of a lot more bad guys out there than what was depicted on those posters.
FNC news alert last night said estimates are 18,000 AQ operatives here in the USA...a few months ago aq claimed their plans were 70% complete---now they are saying 90% complete.
Seems to me that by going public in a high profile way, they force the jihadis hand to move as soon as possible.
OTH, AQ is smart, intelligent and basically underestimated by us, not in specific threats, but the overall dumb ragheads in caves schtick and they may so deep underground in the US, they are confident enough to wait for a time of their choosing before pulling off what they want to do.
Any operational crew requires a support staff.