it does not follow that you must spy one every single citizen and grab every single communication. the more hay you gather, the worse your chances of finding the needle.
” the more hay you gather, the worse your chances of finding the needle.”
Too the point and pithy.
Actually, if there's a needle somewhere in the hay field, you will have zero chance of finding it unless you search the entire field. (Come to think of it, that's not true, as you might find the needle in your first five minutes of search. But I wouldn't place a large bet on it if I were you.)
Unless you have some way of narrowing the location down to some extent. But we can't do that, because it would be "profiling."