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Well, consider the case of lasers used in communication. Being as highly focused as it is, wouldn't it be extremely difficult to detect if not aimed right at us? I realize that it is still EM communication, but it does not propogate in all directions like a radio transmission does. In other words, they'd probably have to be making a directed communication attempt with us, where picking up a radio transmission propogating in every direction might be more likely even if they aren't intending for us to find it. I'm also not sure that SETI is searching in the visible EM spectrum, which is where a laser would be. That's on the more practical side of what another civilization might be using to communicate.

On the impractical and totally unprovable side, I would argue that a civilization a few million years ahead of us may have found some ways to bend the rules. I realize it has no sound scientific argument behind it by our current physics laws, but its something to consider.

Well, consider the case of lasers used in communication. Being as highly focused as it is, wouldn't it be extremely difficult to detect if not aimed right at us?

I do not disagree at all. However, A vast amount of our communications is not designed to be used in a tight beam point-to-point format such as a laser. As we spread thru the solar system, high power EM will become increasing prevalent.