To be fair to Def I don't think he was saying that a spread won't trigger a margin call, just that the spread wasn't the main cause in the case referred to. But the problem of the auto liquidation software making illogical trade choices during liquidation remains under-addressed by IB here.
Due to requests from multiple users this thread has been closed. In the effort to continue the conversation as well as consolidate the subject, please continue to post at the thread below. http://www.elitetrader.com/vb/showthread.php?s=&threadid=226522