I see, so i could remove it for even a cleaner look.
My ultimate thought is that nobody is going to respect copyright, so I tend to upload everything under some sort of permissive license so that their "no copyright intended" thought process ends up being in compliance with the license. Sharing is human nature. A c surrounded in a circle isn't going to change it.
Of course Content ID doesn't always work as intended, especially for works that are owned by ordinary people and not the MAFIAA. But I think the basic idea is sound and hope that it becomes the norm. As you said, sharing is human nature. Sharing should be okay as long as both money and credit go where they should.
Plagiarism is an ethical offense but not a legal one and isn’t limited to direct reuse. It includes using ideas (even in your own words or representation) without attributing them.
Copyright violation is a legal offense and applies to direct reuse (including various forms of “remixing”).
(IANAL, this is not legal advice.)