I think a civilization that intends to wipe out all others would be more proactive.
Pre-seed any nearby system that looks like it could develop life at all with doomsday devices preprogrammed to activate the moment a technosignature is found.
That's a lot of stars, depending how far out you want to build your safety zone, but you only need to send a seed craft that builds the rest of the device.
Pre-seed any nearby system that looks like it could develop life at all with doomsday devices preprogrammed to activate the moment a technosignature is found.
That's a lot of stars, depending how far out you want to build your safety zone, but you only need to send a seed craft that builds the rest of the device.