While the Habush opinion partially relied on the invisible nature of the keyword triggering, I think its logic should broadly apply to all organic search activity.
Unfortunately, traditional endpoint security techniques are not designed to understand the logic behind these attacks the clandestine activity occurring within system processes, those subtle changes necessary to spot potentially bad behavior.
Finally, in an interesting twist of logic, he uses the existence of volunteers, of charitable activities, to prove that volunteers and charitable activity cannot solve problems.