"Burden of proof" is also formally assigned under judicial frameworks. "Presumed innocent until proven guilty" and "beyond reasonable doubt" are examples of such assignations.
Outside of a legal context, I tend to assume that if someone in a discussion has made an appeal to "burden of proof", that discussion is probably not a fruitful one.
You know the drill - If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
And, while this is an accidental exception, future open threads should start on Mondays until further notice.