If SETI discovers alien messages, it seems likely that a lot of different players around the world will also be able to record these messages (anyone with a sufficiently good receiver—I’m not sure how many of these there are right now, but surely more will develop within a couple years of the alien-message discovery).
At that point, I’m not sure if preventing the message from leaking is all that plausible. So even conditioned on all your assumptions, your plan buys the world, what, a couple of years? I mean, unless you think the existence of the alien message can be kept secret, but I highly doubt that.
If SETI discovers alien messages, it seems likely that a lot of different players around the world will also be able to record these messages (anyone with a sufficiently good receiver—I’m not sure how many of these there are right now, but surely more will develop within a couple years of the alien-message discovery).
At that point, I’m not sure if preventing the message from leaking is all that plausible. So even conditioned on all your assumptions, your plan buys the world, what, a couple of years? I mean, unless you think the existence of the alien message can be kept secret, but I highly doubt that.