Here’s where we noticed it first:
https://jamesmendezhodes.com/blog/2018/11/10/best-practices-for-historical-gaming
I really love the idea, and love that it’s catching on. I think it’s great for keeping players from being blindsided either by something happening in a scene that they weren’t expecting, or from having their characters chewed out ICly for something that’s just part of the game world.