During the First World War there were quite a few unofficial ceasefires or cases where soldiers arranged off-target artillery fire. Most of it is anecdotal, since the high command was not involved and would have taken serious issues such events. However, reading letters from the front it becomes clear that these informal armistices actually did happen.

Today such an event would be impossible. After the Second World War it was noted that few soldiers actually fired their weapon directly towards the enemy (it’s somewhat against human nature to kill a fellow man) and training was directed towards eliminating that problem. The military authorities are aware of the problem and are now also focused on producing “killers”, rather than just functional soldiers. Due to such new concepts in military training, modern warfare is far more deadly, when looking at the actions of individual soldiers.

I believe that military commands all over Europe took note of these informal armistices and between the two wars they likewise changed how soldiers were selected and trained (their basic approach to war), so it became more unlikely that soldiers would make such unofficial ceasefire arrangements. Although I have come across anecdotes from WWII, where each side is celebrating Christmas with song, I’m not aware of an actual ceasefire. However, what I’m aware off and what actually happened are naturally two very different things :p