The idea of "buttoning up" a tank was not totally unheard of during the Second World War II and was one of the ways recommended of dealing with a tank if you were lacking in full-on anti-tank weapons in US Army training videos:
[youtube]http://youtu.be/1QgXuhv7-54?t=15m22s[/youtube]
Those are moral videos, designed so fresh infantry wouldn't run away when they see tank approaching.
In reality most of the soldiers who were in situation where they had no choice but to fire their Bazooka's or AT rifle grenade on middle and heavy tanks ended up dead barely scratching the paint.
Bazooka, recoiless rifle, AT rifle nade, AT rifle, etc were last resort weapons that gave infantry in desperate situations some sort weapon to try their luck.
Solider really needed to be lucky and disable treads on the tank or have some lucky shoot to do any damage even with bazooka. And that is from 10 meters away, no more.
Those weapons primary role was to attack light armor, bunkers and fortified buldings, etc.
Its nothing like what you imagined from watching the movies, brave soldiers attacking tiger and destroying it with bazooka shot from 150 meters away.
Damaging scope with small arms fire on tanks is impossible, and only thing that can do any damage is AT rifle.
What some people suggested about crew being shocked from sound of bullets hitting metal, like in the drum is just funny.
Just by being in the tank without earmuffs would make anyone deaf in 10 minutes, hence everyone in the tank wears earmuffs that completely cancels noise and communicate only through radio.
Yes, I was in the tank and yes I know I wasn't in the world war 2.
None the less, that is reality, game is not reality so lets not mix the 2