You follow the link to a promising lecture or videotaped evidence of some bombshell on YouTube, and get the following error:
Video unavailable
This video is no longer available because the YouTube account associated with this video has been terminated.
Now, I’m no YouTube expert, but I suspect more often things are backward.
If Google were honest, I suspect, they would say this:
Video terminated
In fact, this whole YouTube channel is no longer available because the video associated with it must be made unavailable. (Terminating only the one video arouses suspicion.)
(Tip: try searching for the exact video URL.)