According to this Lindybeige video there have been instances of WW1 enemy soldiers coming across each other, putting down their firearms, and yelling and throwing rocks at each other instead of engaging in a battle. How many documented instances of this have there been and how often did it occur?
Follow-up: do other facts he presents hold value? In this (https://www.youtube.com/watch?v=zViyZGmBhvs&feature=youtu.be&t=17m14s) part he says he got a figure from a documentary he watched on telly, and on other facts he doesn't cite any sources. Also I don't think he got it right on psychopaths (he said psychopaths can't recognize the fear on a person's face when they're shooting at them).
Be wary of using him as a source, he's very well read and I'm willing to believe most of the things he states are true but he doesn't methodically post sources in his video (it'd be a pain in the ass to do with time stamps, and would be sloppy without them IMO but better than nothing) and often uses documentaries and memoirs as sources. Really good for specific stories and battles, not as good for science and recognizing trends (such as is the case for your question)
Sorry if your seeing a reply got your hopes up but I felt this had to be said, if not for you then for everyone else that reads these comments