for me reading this post the problem I see is that when newer accounts do something like this it is seen as suspicious

Take a look at this post
https://steemit.com/utopian-io/@crokkon/cashout-chains-steem-from-7400-accounts-leaves-steem-via-only-a-few-accounts

so seeing older accounts do the same thing is also suspicious

You see cash out rings could be a few things. And as you say Hive account@blocktrades one could be that the person just wants to keep their transactions private ( but that then opens up the question on what is right or wrong with having alt accounts and how many is enough?)

I am sure you are familiar with the EU AML regulations. Having studied this in detail as a CPA auditor, these are the kind of things that would raise flags when doing an Audit. I guess its in my training.

So I would say nice find because there is a heap of data to look at to find stuff like this, and a serious amount of time must have been put into this. Maybe the point is 'Big brother is watching' so if there are people thinking of doing something not in favor of the community , posts like this might put them off