Well, then it would seem that SETI is not science.
The most crucial difference between SETI and ID is that SETI admits up front that it hasn't found what it's looking for.
Actually, SETI really isn't scientific. It, like ID, operates on the basis of a priori probability estimates, which are necessarily both unfalsifiable and unconfirmable (sort of the worst of all possible worlds scientifically).
The idea that purportedly improbable regularities signify intelligent action is at the basis of both, and is rot.
How, if one found, say, a 'first thousand binary digits of pi' repeating beacon 850 light years hence, would you either verify it had an intelligent source or disconfirm it? Sure 'in principle' one could build a self-sustaining starship and send it off, wait a few millenia and one's descendants might get word that there was a city on a planet at the other end, or a really wierd orbital configuration of neutron stars, or whatever. But 'in principle' one could reproduce conditions for an evolutionary event and rerun it to falsify ID.