No, its perfectly legal.Its a twin pronged way of investigating...

No, its perfectly legal.
Its a twin pronged way of investigating what sort of orders are being placed behind the scenes (in the dark pool of off-screen orders)...these bots put out under and over market-price buys and sells in order to catch-out (like a dragnet) a stop loss order etc and to simply accelerate what is already in the market to happen.
They threfore dont orcehstrate anything but hunt out those who have.

And on a different note, they can orchestrate with this type of bot prdering...but it involves much mcuh higher volumes to do so and they are what is classesd as an Ambiush tactic.
The tactic used recently is moreso i regard as a stealthy investigatory trigger tool. Had there been any biug orders around, they would therefore have been filled and contributed to the volume weighted average price, just like the smaller tardes were. So there was no advantage in the bot activity, it merely endeavoured to accelerate trades, not manipulate them.

Cheers

L