The problem is that even some remote robots left alive guarantee a second strike on the attacker. So any dark forrest strike would have to be engulfing the whol

The problem is that even some remote robots left alive guarantee a second strike on the attacker. So any dark forrest strike would have to be engulfing the whole solar system. I think we would detect such events by now. Unless you can manage to disguise your strike as a "natural" disaster. The Pulsars rotation angle just tiled and the rays emitted cooked the system. A tragic accident in a unjust, unfeeling universe. May they rest in pieces.