Re: German Infantry Squad Manual
Neat video. Note the use of smoke near the enemy position and how the squad fires its weapons through the screen, then throws grenades and assaults. A choreographed training film to be sure but not something you ordinarily see in Hollywood films either.
Likewise in the PDF concerning tanks (p.78): "Frequently the tanks are equipped to provide smoke clouds in order to cover the closely following infantry.In this case all machine guns and rifles will open rapid fire into the smoke screen for the purpose of inflicting losses upon any infantry advancing with the tanks."
Not meaning to flog a dead horse but z-fire is both demonstrated and encouraged in these combat training aids.