Ironically, during the war, Koster, as a German citizen, was considered an enemy alien and was kept under partial house arrest.He had to stay in his house in the evening.

• 令人啼笑皆非的是，第二次世界大战期间，科斯特由于是德国公民，被视为敌国侨民，遭有限度软禁，晚上得留在家中。