Well, if the rocks are sufficiently small and plenty as well as stealth coated (or at least painted black) they are still a nuisance with deadly potential.
In The Expanse the group responsible for the attack stole the most advanced stealth coating in the Expanse universe to paint the asteroids, leaving Earth unable to detect them with anything but their most powerful sensors.
Well, if the rocks are sufficiently small and plenty as well as stealth coated (or at least painted black) they are still a nuisance with deadly potential.
In The Expanse the group responsible for the attack stole the most advanced stealth coating in the Expanse universe to paint the asteroids, leaving Earth unable to detect them with anything but their most powerful sensors.