I don't think the average person understands copyright law at all. You can peruse YouTube and look at all these videos that are re-uploaded versions of other people's videos and they all say "no copyright intended". That is not how any of this works. People learn about plagiarism and "academic honesty" in school, and think that as long as they don't claim the work as their own they are entitled to make money off of it. Turns out: not true.
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.
When YouTube's Content ID system is working as intended, people will not make any money off of their "no copyright intended" copies. Whoever owns the original work will (if they allow 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 and copyright violation are not the same thing.
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”).
