Even though the rules are pretty strict about plagiarism, I think the moderators can easily spot what is actually done intentionally and what isn't. Accidental plagiarism is a thing though, you might unintentionally forward information or text that someone else has already wrote about.

I think it could be compared to music - a lot of times some pieces that are already written come to mind to another musician (happened to me to write a very similar part of a song even though it wasn't in my mind). So, sometimes it would be logical to write something, unknowingly plagiarizing the original contributor.

Even though we must be alert about this, misunderstandings can happen.