This a very good point, especially with the video we just seen. However, we have to remember, our snakes are not in the wild. They don't have the option of when they are tired of their buddy, to leave. We honestly don't know enough about the subject to go either way. Maybe they only stay with others during breeding season. There are just too many "ifs" involved to make any solid statement.
That's why i do what i know. I know when kept separate it's easier to notice illnesses, clean, as well as feed (for those of us who wish not to disturb the snake during feeding process).
Until anyone can show me how the snake (not us) gains an advantage over having a cage partner, separate is how I feel it should be done. Of course, I'm just as stubborn as the rest of you, and refuse to do it differently.