Greetings,
Actually, moving vehicles are quickly picked up by both fixed and rotary wing - dust or no dust. The movement is what catches the eye.
Relook at the actual history of WWII, TAC AIR was down right devistating when used on armored formations; Falaise Gap, the rush through France, the Bulge (once the weather broke) and units were moving in open terrain.
It is unfortunate the GVs can't hide in a bldg or under a tree, but the low level required to see the icon is reasonably fair.
Regards,