There is definitely an issue of many permabanned users getting merit. I think the main issue is that plagiarism is hard to detect and often fools the reader into believing that it is a good quality post.
Permabanned user getting merit doesn't mean that merit was sent for e.g. plagiarised posts. tvplus006 and lovesmayfamilis are notable scam researchers and got a lot of merits for that work. Later turned out to have plagiarised in the past.
https://bpip.org/profile.aspx?p=lovesmayfamilishttps://bpip.org/profile.aspx?p=tvplus006I believe chimk ended up at the top of the list mainly because of users like that, and not because of lack of due diligence in sending merits, let alone
corruption.