I think it's possible. There was a case back in September [1] where six "third-party sellers consultant" were charged with allegedly bribing up to ten Amazon employees to restore deleted items.

Of course, those people were caught and that goes against the "not detect this problem" part. But if you were to scale down this operation from 16 people down to just one or two, it seems like it could work.

[1] https://www.cbsnews.com/news/amazon-marketplace-fraud-scheme...