I was surprised to read that the honor system of parole was still functioning in at least one case during World War I. The Telegraph reports:
Capt [Robert] Campbell had languished in the Magdeburg prisoner of war camp for two years when he received word that his mother, Louise Campbell, had cancer and was close to death.
He wrote to Kaiser Wilhelm II, begging to be allowed home to visit her one final time.
And incredibly, the German leader granted his request, allowing him two weeks leave, including two days travelling each way by boat and train, as long as he returned.
The only bond he placed on him was Capt Campbell's “word” as an Army officer.
The young soldier returned to his family home in Gravesend, Kent, in December 1916 and spent time with his mother before returning to the camp, where he was held until the war ended in 1918.
There's more at the link.
Sadly, the concept of personal honor has largely fallen by the wayside in today's materialistic, "if-it-feels-good-do-it" world. I daresay that if a present-day US officer gave his parole and was permitted by an enemy to return home under similar circumstances (unlikely though that is), the US authorities would probably refuse to allow him to return. That's a sad commentary on our modern world, IMHO.
(Why, yes, I have been accused of being a cultural dinosaur on occasion. Personally, I attribute it to early-onset curmudgeonhood!)