When you get behind an AI tank, they generally just remain stationary until they're destroyed, but their vision towards the side can be extremely good.
Take the situation in the example below. A T-34 that starts the phase buttoned-up moves forwards and, like a gunslinger in a Western, turns its turret and accurately engages a Panzer 38(t)E in light woods through a row of trees. Trees in general don't seem to do a good job of hiding a tank, tanks (both mine and those of the enemy) are experts when it comes to firing through light woods.
Sometimes, AI tanks just move forwards and get butchered by an attack from the flank, but there are also other times when one of the flanked tanks turns its turret and fires at my ambushing tanks with perfect accuracy.
