[koheripbal]

Which is why the expected strategy is to seed all systems with autonomous berserkers. ... and/or have them meandering from star to star to report/destroy civilizations in their infancy upon detection of radio signals.

You'd need trillions of them per galaxy, but that's well within the capability of a type III civ.

It reminds me of the extra solar object detected a couple years ago that buzzed the Earth and then mysteriously ACCELERATED out of the system.

So assuming we were just detected and assuming there's a berserker in the system already (likely in an outer orbit) that would imply we have only a couple decades left.