I'm really fascinated by the idea of information flow becoming inadvertantly bi-directional when observation becomes too obvious. Everything turns on the question of praxis. The Allies have to be careful not with how much information they collect via codebreaking, but rather how much of that information they put to use. Information is a funny thing because it relies on the interface between pattern and randomness to be communicative, which is another way to say that data is only meaningful/useful if it can be differentiating from other data. Finding pattern in the noise; it's basically an extremely large-scale sifting process.