Censorship, or What was / was not allowed in 1959

A number of commenters have remarked upon the fact that this film was made in Germany less than 15 years after the end of the Third Reich. We see Wehrmacht soldiers and officers; we see local Party officials; we see keen young lads identified as members of 'the cadet corps' if not explicitly the Hitler Jugend. One thing we do not have, however: nobody in the entire film, not even once, says the words 'Heil Hitler'. That can't simply be a coincidence.