In an insurgency, the core must be protected from the government. The easiest way is to never expose more than a couple (or 7) insurgents at a time. How it works, at no time, until fully prepared do you allow any one person to know any more than 6 others. If one gets captured, that one can only snitch on 6 others, (because he litterally knows no more than his group) but cannot give information on the core cell. works the same for espionage
That is how the communists have worked it for years. Not a commy basher...just a statement of fact. The CIA probably uses the same.