I have have been checking people´s post myself, and I have flagged several posts for plagiarism. You can prove it for yourself, or I can prove it for you,
it´s all in my comments and replies. I only flag after I find the evidence however, and I give the links for the original, so that everyone can see why it´s flagged.
If you are going to flag, DO THE RESEARCH FIRST, AND THEN LINK TO IT!