Well, you can send them the list, so they could at least check those people's activity to find out if they are really cheating or not, but come on, I'm pretty sure some people already posted them Support Tickets about this problem, but since they are the top-spenders Nutaku just ignores that fact, even if they are using macros or whatever.
But, basically, those would be just top 10-50 in the Ranking.