The law requires every order submitted must be intended for execution. Not to pump price or provide the illusion of liquidity. There are 10's of millions of orders that are submitted and immediately cancelled. Why not require a minimum time that all orders must wait before they are allowed to be cancelled? Tie the minimum time to the exchange and fair access to to the execution venue. 25ms may be sufficient to bring parity in the US markets allowing market participants to take on the trade opportunity via websockets if access is limited to US based clients. Globally accessible Markets should have a minimum wait equal to reasonable ping times so all participants are at least given the opportunity to take on the trade opportunity. ie. CME products: 250ms. An exchange may run lower minimum times if they require market participants to colocate. ie. 1ms or sub 1ms. But than all participants are trading at wire speeds at the venue. Clients of these fast market exchanges would piggy back on their brokers infrastructure to gain access. Make it the responsibility of the exchange to provide fair access to all market participants. As it stands even computer to computer is unfair and human to computer is silly.