It actually amazes me that people do manage to track down some cases of copying. People who get caught out should be watched more.
There are cases where artists make their own version of work by others. That can be valid, but they have to give credit to the original artist. That can apply to music covers too. Ideally the original artists would be on Hive and we could give them a cut of the rewards.
I was just talking about that with a colleague in EOS Detroit the other day. I think stuff like you are talking about falls under the parody realm and there is a little more leniency there. I agree with you about the catching it thing. There is so much content out there and so much published here daily that it takes a real bloodhound to track down the plagiarized content.