Hot & Hi. You miss my point. Obviously if there is aircraft structure in the way you cannot see anything below you but if it is offset than it becomes visible.
I was referring to my experience doing Fighter affiliation with helicopters when I was in the military. Properly flown with the advantage of camouflage a helicopter is very difficult for a jet jockey to see. Not knowing where it is jet has to have to have a wide scan and cannot concentrate on one point where they may pick up the helicopter, similar to a look out for a civil fixed wing.
You put on one blade without any paint on it and it jumps out of the ground at you!
That is why when a pilot, fixed or rotary, looks at the ground for simple positioning then striped rotors will indicate it presence.