Hello @xpilar, this is a really important topic.
In the Project Hope community we are also making a big effort to stop them.
Weekly we silence many posts that are clear cases of plagiarism.
But, many times they are very clever, make some modifications, paraphrase what they copy to try to confuse. It's a complex job, because it involves spending time reading, comparing different texts. It really is a job. But as @stef1 says, we must all be guardians. I find it difficult for any of us to just verify that all the publications in all the communities are original. But if every moderator and even every honest user does their part, this bad habit of some who take advantage of plagiarism could be diminished by a lot.

Some way to engage the efforts of those who find these plagiarizing users could be an excellent tool. I agree.