I am all for extra, extra, extra efforts and safeguards to stop plagiarism on the Steemit platform - and especially (separately) I am for NOT letting the feeds be filled with 2500 or so re-packaged versions of the same news headlines and stories that are really just cut and paste junk (like the clickbait news sites that fill FB with re-copied articles).
The intelligence level of this community deserves to see original material promoted almost exclusively, I feel. People can "share" videos and news stories all they like with no reward (for all I care), but with the overall profit motivations of posting on Steemit involved, this will get so out of hand real quickly if not nipped in the bud, it could make the site and many feeds irrelevant. Post videos yes, but I'd vote that if re-posting material here that is already on YouTube, Vimeo, etc, it should almost exclusively be allowed to only promote material that the "poster" (account holder) has the copyright to or some very legitimate claim to originality.
To avoid copyright infringement in general - from what I know anyways - detailed commentary avoids those lawsuits under "critical review" law - esp when disagreeing with the quoted material - but limits the use of copyrighted material to only posting primarily excerpts of the copyrighted material, not the whole thing. (And esp not over and over and over again in my news feed, is my plea here!)
Sorry for the essay, but see https://en.wikipedia.org/wiki/Fair_use
and notice the very first sentence has the word "limited". Fair use does not allow 100% reproduction of someone else's work, and is even stricter when a motivation to profit is evident. I feel this HAS to be Steemit's stance/guideline/enforced rule.
"Fair use is a US legal doctrine that permits limited use of copyrighted material without acquiring permission from the rights holders. "