While I can't verify that the trading volume leaderboard is accurate, I can say that it SEEMS to be accurate. I've played reset a few times in the past week and a half, and checked those leaderboards each time, and my movement up the boards correlates to how many trades I've made. If I assume that they are accurate, then I can tell you that you CAN see within the first 30-40 minutes EVERYONE who has made a trade at reset, because there are often players listed on the board who have 0 trades- in other words, the traders with stocks moved peters out around 85, with that 85th trading 1 share, and then no one else has any trades moved. That's how I see if there are any obvious manipulators by looking at their handles.
Now, granted, there could be a smart trader who has set up dummy accounts with varied names that aren't obviously related, but who could identify them? And plus, according to your theory (which I also suspected a while ago before I started this informal study) there should be 10-20 accounts all with the same amount of trades made, something nice and noticeable like 100k or 99k or 400k. And there aren't. The spread of # of shares traded is wide, and there are very few overlaps.
Keep in mind that this is only within the first hour of reset, at which point more than 100 accounts have usually made trades. But that's usually the window of reset where manipulation WOULD have happened.
And finally, aside from the few accounts I've noticed that have very similar names, and which I've reported to hsec, most of the rest of the accounts that are listed have been account names that fairly impeachable, at least in my mind.
Unscientific, but my "proof" that manipulation, at least in the manner of which you speak (and which I was worried about) doesn't happen.