The SETI assumption is that some alien civilizations want to make themselves known, and radio is the easiest way to do this. It would mean committing to a long

The SETI assumption is that some alien civilizations want to make themselves known, and radio is the easiest way to do this. It would mean committing to a long term project of beaming powerful radio signals at candidate star systems. So we just need to scan radio frequencies for enough stars before we stumble across a beacon.