That didn't take long. On Feb. 8, I posted to YouTube a clip taken from the Super Bowl: not the football, but the copyright warning the NFL stuck into the middle of it, wherein they tell you it's forbidden even to share "accounts of the game" without the NFL's consent.
Their copyright bot didn't seem to see the fair use in my educational excerpt, so YouTube just sent me their boilerplate takedown. Time to break out that DMCA counter-notification.