If the ETI are advanced enough, they won't need RF
They will have the ability to monitor stars that last long enough to have life and examine their planets for all the telltale signs of life. We will be able to do this in the next 30 years, so imagine what an advanced ETI could do.
See Robert J. Bradbury's Web site for some ideas on such civilizations and their capabilities:
http://www.aeiveos.com/~bradbury/
