Most of the armed ground vehicles in ARMA 3 have very powerful optics that let them easily spot and accurately engage enemies at ranges of more than a kilometer. This can make it very difficult to fit them into multiplayer combined arms missions outside of a few types of terrain, as they tend to annihilate anything within line of sight.
Currently, there are a few commands that limit vehicle optics (disableNVGEquipment and disableTIEquipment) that help balance things out a little. Additional commands should be added to give mission makers more options for fitting vehicles into their missions. These might include:
disableRangefinder -- Hides or otherwise disables vehicle rangefinder.
disableMagnification -- Disables magnification beyond the "normal" right click zoom.