Mistakes may occur but it must be taken case-by-case and then making the decision. who made a plagiarism from a high quality topic and  making an effort  is not like who copies the first result of Google's search or want to get more merits for paid posts.

Generally as long as plagiarism is prohibited, all members and all the ranks are the same as the same.
Unfortunately,  high-ranking member have a chance to try to justify their position more than newbies.