Yes it is just a game, I dont think they gave too much thought on a video like the one you're describing.
However, if the soldiers were walking beside the tank, they were using it as cover, to protect themselves from enemy fire, maybe. Think about it, when the enemy just doesnt have anything against tanks (if thats the case), and they're just trying to take out the infantry before they retreat, then the tank would provide great cover against them. But I dont really remember that vid you're describing (its been almost 3 years since I played WiC, cant remember everything), so.....yeah
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