In de Maupassant's Two Friends, why does the colonel allow the two men to go into a warzone?

Question

In Two Friends by Guy de Maupassant, the two men wish to go fishing in a warzone and are allowed to do so by the colonel who controls the checkpoint between the safety of Paris and the warzone outside of it.

An hour later they were walking side by side on the-highroad. Presently they reached the villa occupied by the colonel. He smiled at their request, and granted it. They resumed their walk, furnished with a password.

The corresponding passage in the French version, "Deux amis" goes as follows:

Une heure après, ils marchaient côte à côte sur la grand'route. Puis ils gagnèrent la villa qu'occupait le colonel. Il sourit de leur demande et consentit à leur fantaisie. Ils se remirent en marche, munis d'un laissez-passer.

Knowing full well they might die at the hands of Prussian soldiers, why does the colonel allow them to leave Paris?

Answer 1

M. Morissot and M. Sauvage (note: they both have the sound "so" in their name, meaning "sot", or "stupid" in French) first have several glasses of absinthe.

_{Ils ( . . . ) burent ensemble une absinthe. ( . . . )
« Une seconde verte, hein ? » M. Sauvage y consentit : « À votre disposition. » Et ils pénétrèrent chez un autre marchand de vins. Ils étaient fort étourdis en sortant, troublés comme des gens à jeun dont le ventre est plein d’alcool.}

_Translation:

They had an absinthe.
"Up for a second green?"
M. Sauvage agreed: "As you wish."
And they entered in another liquor store. They were strongly stoned as leaving the store, like hungry folks with the guts full of alcohol.

At this time they are drunk, hence they are adventurous and over confident.

Then later:

_{Si on y allait ?
– Où ça ?
– À la pêche, donc.
– Mais où ?
– Mais à notre île. Les avant-postes français sont auprès de Colombes. Je connais le colonel Dumoulin ; on nous laissera passer facilement.}

_Translation:

So, shall we go?
– Where to?
– Fishing.
– But where?
– To our island. French outposts are near Colombes. I know colonel Dumoulin; I will let us pass.

M. Morissot and Colonel Dumoulin know each other, so colonel Dumoulin accepts as a favour to M. Morissot. When he sees these two friends looking brave by the alcohol, the situation seems funny to him.

Another detail is that at this moment, the Prussians are up in the hills, and the fishing spot is hidden, so they don't expect to be caught:

_{M. Sauvage, montrant du doigt les sommets, murmura : « Les Prussiens sont là-haut ! »}

_Translation

M. Sauvage, showed the up hils, and whispered: "The Prussians are up there!"

They take precautions to go to their fishing spot:

_{Et ils descendirent dans un champ de vigne, courbés en deux, rampant, profitant des buissons pour se couvrir. ( . . . ) Une bande de terre nue restait à traverser pour gagner le bord du fleuve. Ils se mirent à courir ; et dès qu’ils eurent atteint la berge, ils se blottirent dans les roseaux secs. Morissot colla sa joue par terre pour écouter si on ne marchait pas dans les environs. Il n’entendit rien. Ils étaient bien seuls, tout seuls. Ils se rassurèrent et se mirent à pêcher. En face d’eux l’île Marante abandonnée les cachait à l’autre berge. La petite maison du restaurant était close, semblait délaissée depuis des années.}

_Translation:

So they descend into a wine yard, bending, crawling in the bushes. A narrow open land was to cross to go to the river shore. They ran, and when they ended at the shore, they hid in dry reeds. Morissot listened to the ground to hear if someone was walking around. He heard nothing. They were alone. They relaxed and started to fish. In front of them, the Marante Island, abandoned, hid their spot. The little restaurant house was closed, looking abandoned for years.

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TL;DR

The two friends are over confident from drinking, and the colonel personally knows one of them. Also, the Prussians are up in the hills and the fishing spot is hidden so they think they could be safe.