I admit, this post is being made largely in frustration, but I feel it's a valid frustration. See, if a troop stands in front of a chest-high wall, or a kneeling comrade, he can shoot over that comrade with no difficulty. Or, if they're not directly adjacent, the game is polite enough to inform me that there's an obstacle, and the percent chance that he'll hit his friend/wall.
Tanks apparently not only lack the ability to shoot over things much shorter than them, but also the game feels no obligation to warn you. So now my laser-cannon tank is at 1/3rd HP and three of my top soldiers are goo, all because I assumed that I positioned the tank so that the barrel was literally extending over their heads, the shot fired would ALSO go over their heads.