YouTube's copyright system is kind of a mess.
I wanted to add background music to a video, so I tossed in some public domain Bach music. The video got flagged as breaking copyright laws; a company named "Ad Rev for Rights Holder" claims the music belongs to them.
It doesn't. The original music is public domain, and this particular recording of the music is also public domain. A quick check online ensures that this is not the only public domain material on Youtube that Ad Rev has flagged as their property.
I disputed the claim, and this is where things get crazy. Guess who gets the decide whether or not my dispute was valid? If you guessed "an unbiased third party", you're wrong. If you guessed "YouTube", you're wrong.
No, Ad Rev got to make the final decision. Unsurprisingly, they ruled in their own favor. Which means, among other things, ads will automatically appear on the video, and all profits will go straight to Ad Rev.
So, sorry everyone! I deleted the video, and you won't get to see it.