From a gameplay perspective this just plain sucks for reasons I shouldn't need to get into.
From a realism perspective: tanks have several mgs on them, hull, coax and turret, and these all create a devastating cone of fire against infantry. The guns in CoH are awful and don't do them justice at all. No one would actually be able to get into close range. The only places where things like this happened was in urban combat, which tanks were ill suited for. Also, random infantry couldn't even drive the tanks of their own country let alone one speaking a different language altogther. Lastly, the tank crew also had personal defense weapons and the tank had a lockable hatch. So you couldn't get in if you wanted to anyway.
Fun fact: Germany developed a curved barrel for their MP44s which allowed it to shoot round corners. The stress of changing direction shattered the bullets and they came out like shotgun pellets. This made the range practically unusable for normal combat but it turned out that it was really good if Russians were on the outside of the tank and the crew needed to hose it down. It was like a rapid fire shotgun that didn't expose the user to counter fire.
If you get into an argument with me, you're wrong.