You really think Sarao caused the flash crash? Have you read the evidence against him? It's pretty slim at best. He's just a patsy.
I talked about this issue in another thread. I don't know if he's guilty or not. The fact is that the big boys does spoofing (trading), layering are illegal but the big boys get away with it maybe due to the fact they are better at hiding it although some firms have been caught and heavily fined, barred from exchanges and suspension of license.
In contrast, there's been a few articles on bloomberg and reuter in which the biggest complaints about algo retail traders and algo private traders doing spoofing has been by the big boys themselves. Usually these algo retail traders or algo private traders are former institutional traders or former quants at firms.
I believe when Sarao (a private trader...not retail trader) is a
scapegoat for that particular "flash crash". The CFTC, CME and Department of Justice needed a scapegoat and they ignored the big boys that were doing the same on that day but went after the private trader with a big bank roll that was doing the same. He was easy pickings because of his former connections with a institutional trading firm and he was doing it in large position sizes...they will need to prove that the program was designed to "defraud" (see article below about such involving someone else arrested that was not a private trader but a small firm).
Ironically, firms gotten smarter and know "not" to do such in large position sizes. They now do it in small sizes as in example involving the Emini ES futures involving 1 - 5 contracts but more often.
To further the contrast, read the article about Mr. Coscia for doing the same but he didn't cause a flash crash @
http://dealbook.nytimes.com/2014/10/06/a-new-crime-with-a-catchy-name-spoofing/?_r=0 (my article is about the same Mr. Coscia that
Deuteronomy_24_7 posted about but my article occurred a few years before Mr. Coscia conviction)
I read in another article (I'll post it when I find it again) that up to 85% of the orders placed in the S&P 500 Emini futures are
"cancelled". That's scary info for those trying to trade the Emini ES futures via analysis of the Bid/Ask screens and DOME traders.
Thus, it seems like anyone can cancel an order via an algorithm but the key is to prove that a program was design to do such for the purpose of "defrauding" regardless how little profit you made.