First off, I'd like to state that I only speak for myself, and not for Steemcleaners or anyone else, but these are my thoughts on plagiarism. (I suspect that Steemcleaners has higher standards.)

If you are making a post and are worried that it might get flagged for plagiarism, then here is the magic phrase to use:

"I did not create this content"

There you go, put that phrase somewhere in your post, preferably next to whatever picture/music/video/article that you are sharing, and you will be 100% safe from my flags (and most others I think).

"I did not create this picture"
This picture is amazing! I wish I created it, but I didn't. The actual artist should pat him or herself on the back.

Obviously, if you can specify that artist and link to the original, you should do this. This will make your post more valuable, more likely to receive upvotes, and you'll be that much safer from any flagging.

The above pic I found at https://www.neondystopia.com/what-is-cyberpunk/ I'm actually not sure who the artist is, but if someone lets me know, I'll be happy to add it to the post.

But what about copyright?

To be honest I don't care much about copyright laws. Those laws are just laws made by pesky governments, and it's not my job to defend copyright: I just fight against plagiarism.

I am a Kopimist with regards to my views on sharing data.
https://en.wikipedia.org/wiki/Missionary_Church_of_Kopimism