But behind the algorithm there is a human trader with motivations and market knowledge who is commanding it; the fact that the buyer is, in some technical sense, an algorithm doesn't seem very relevant to me.
How A Book About Flies Came To Be Priced $24 Million On Amazon: https://www.wired.com/2011/04/amazon-flies-24-million/
Again, that's what you'd think and it's technically true that you can know who is running what system, but the systems are too complex to say they are really working on behalf of anything except the rules of min/maxing.
How do you explain bidding the price of a textbook up to millions of dollars is "working on behalf" of anyone?