One of the problems I have with the terrain editor placing down tank objects, I cannot turn of shadows. So when I inspect my handy work from a road after hiding a tank in some trees with the help of shadows, the tank is hidden in plain sight. Online with shadows off, you almost cannot place a tank far enough off the road to hide it.
If a guy with a bomb hunting for a GV in the trees has shadows off, he will find you if any part of you is exposed to sunlight. With shadows off, tanks light up in the sunlight. Tank town has four high hills covered with trees that are the best sniper hides in the place.