The thing about many of our markets today is that they are international, with different rules in each jurisdiction. Supposing you implemented this system in th

The thing about many of our markets today is that they are international, with different rules in each jurisdiction. Supposing you implemented this system in the entire US, the HFT firms would simply shift their efforts to trading venues where order books are not quantized. Then they would take the real-time information and take advantage of the US exchanges. Think about the billions (trillions?) of trades that occur on minescule timescales now and how often we have flash crashes. Sure, HFT algos interact with one another constantly, but flash crash investigations have uncovered both human (manual entry) and algo error as their root causes. Part of what makes flash crashes more severe is when HFT safety protocols kick in and they remove their orders from the market, causing liquidity to dry up and exacerbate the crash.