If system errors leading to erroneous executions, depegging, and massive liquidations during a flash crash occurred on the CME, the CME would likely adjust prices or cancel trades deemed market disrupting due to system defects or improper use of the platform. Can see this in the CME's rulebook: http://cmegroup.com/rulebook/CME/I/5/5.pdf I've had the CME once cancel my trades during a silver flash crash.(Alex Krüger)