Well its kind of hard for a rifle squad to fire at a Marder 100's of metres away
I would not worry about that one. Unless they have an AT rifle, shooting at the thing is a bad idea. Unless its shows its back side and infantry can hit the gunner/loader. But you can influence these things a bit. The concealment command for instance. I usually have this ON. But if trenched for instance, turning it off gives a better view to the infantry and they shoot more/hit more. But can be hit too.
But your LOS tool from your unit to target works both ways. But seeing where the enemy is looking is BAD with a tool. This would give you too much info. Like if a vision device was damaged or destroyed. Or even how many crew are still alive in the thing. This sort of info gives a massive advantage to player if misused. In the end. I just get the camera to the ground and take a look if I really want to know. Often get rewarded with some cool thing happening.