Delay every trade by 10 seconds. Not only does it prevent spikes like this, but it will ensure trades done with thousands of transactions per second by software

Delay every trade by 10 seconds. Not only does it prevent spikes like this, but it will ensure trades done with thousands of transactions per second by software are brought down as to not cause stupid crashes : http://en.wikipedia.org/wiki/2010_Flash_Crash http://en.wikipedia.org/wiki/2010_Flash_Crash