You missed the point. Without doing it digitally, they have no meta data to work with. If this is all they are employing, then it is very easy to render them, blind.
I have a military history of crypto repair and analysis to the point of being on a team learning all of the new toys from the actual engineers who designed them from inside all of the skunk works that employed them. I would wager that I know far more about the methods they are using than you can even imagine.
Not to seem contrary but I think you miss the point. Metadata encompasses more than just digital info; that's just the easiest to collect. Social networking theory encompasses more than Facebook and Twitter. If you care about this stuff then you should read the links I posted above.