they'd have to not get caught because right now, with the NSA leaks, large governments are not looking too people friendly.  

I suspected in 2001 the NIMDA internet infection was a government attack due to the incredible level of sophistication at that time.  But, when I analysed it for a week, the "heartbeat" came from IP addresses allegedly coming from North Korea.  Doubting that North Korea could possibly launch this sophisticated of an attack, i suspected that the government doing the attack was smart enough to pick a scapegoat.  

so, in the scenario you describe, the question is, how will they create the scapegoat?