Yeah, the mod has been very careful with the ban button now; what they often do is delete the plagiarist post if it's a one-time offense; we're already losing traffic due to low activity on the forum, so I understand why the mod has been so kind.
You need to check the plagiarism post thread; maybe there is a different, more honest moderator working there, as I see "good" in my reports.
Some of the plagiarism cases I reported via the "report to the moderator" button were left unresolved last year, but I'm relieved to hear that we now have an active moderator on those cases. I'll go over my cases again and report them again, I guess.
In addition, I observe a pattern, the one who has one plagiarism will definitely do more. You just need to check more carefully.
You are right. Real plagiarist don't hide for long
A smart plagiarist can escape ban if they delete the evidences before a moderator handles the case.
That's why we always archived evidence before reporting, so the mod doesn't have to go through all of your posts. Most mods base their decisions on archived evidence, so deleting your posts won't help you much; it will only prove that the user plagiarized on purpose.