Does it perhaps ever occur in nature?

Notice how, say, the Andamanese are entirely safe from online phishing scams or identity theft.

1. Andamanese ))
2. Maybe alien nanobots control part of the galaxy which is concurred by host civilization and prevent any other civilization to invade or appear.
3. Observational selection: we could find our selves only in civilization which berserkers have high attack treshold (or do not exist).