I am not a fan of flash orders but a few nit-picks: - I believe you have to opt in to have your order flashed. You seem to be suggesting this is happening behi

I am not a fan of flash orders but a few nit-picks: - I believe you have to opt in to have your order flashed. You seem to be suggesting this is happening behind traders backs - Only one market in the US still supports these types of orders. It may have happened hundreds of times while reading your sentence but that is a tiny fraction of executions occurring across all exchanges during that time-frame.