I don't think it's fantasy at all, especially after talking to this expert. You'd identify the individuals/companies who own the equity curves, and just intercept orders at an earlier point, like at the ISP. Or, hack the PC that houses the source code for the system.
Anywhere there's big money, there's an attempt to collect sensitive data illegally. I never said it was an issue for us small fish. Imagine knowing that Soros had made a decision to aggressively short the pound? Or that GS had decided to dump Apple?
Haha you've seen too many movies GB. Yes, technically if it's connected to the internet it can be hacked, but it's highly unlikely, for something to be hacked it needs an actual vulnerability to begin with, a buffer overflow or remote code execution or some kind of weakness in the code, you can't just "hack" things like they do in movies, there needs to be an actual weak point that can be exploited, all these hacks you hear about in the news are 90% social engineering, someones account got hacked, or some website got hacked and data was released, pretty much always social engineering, tricking someone into thinking you're someone who should have access, or building a replica fake site that looks exactly like the one they have to login to, where you then intercept their login details, a MITM attack.
In a up to date system, which if a brokerage and ESPECIALLY an ISP DIDN'T have would be incredibly stupid, there isn't much chance of it being hacked. It's just not that easy, nearly everything is encrypted these days, everywhere you login, everything you transfer, so the different points at which you would need to gain access and/or intercept would be insane.
Then you have honeypots and firewalls and tons of other stuff to make it even harder, then once they're through all of that, to be able to find Soro's position on the pound is just not possible, however juicy in our minds/imagination. It would probably be easier to hack Soros himself than hack the brokerage he uses and the ISP.
Us small fish are actually the ones that are probably more vulnerable because the big fish and especially ISP's would make sure they have decent security simply because of the funds/knowledge they have. People and pathetically easy passwords are the weak part, not the systems themselves connected to the internet.
Plus we kind of can tell when big positions are put on, it's called volume isn't it?