There was an article in the April/May Trader Monthly mag :
"Peterffy to CITI:No do-overs"
When regulators mull new rules, they often quietly consult Thomas Peterffy, the powerful founder of options-market-making titan Interactive Brokers Group. Peterffy, it seems, is a stickler for rules. When Citigroup recently made an inadvertent QQQQ order (a bad data feed led to an automatic fill on 950,000 contracts, leaving Citi holding an $18 million loss), two market makers, Wolverine and Morgan Stanley recognized the goof and agreed to bust up the trade, knocking Citi's loss down to &7 million. However, IBG's Timber Hill showed no such mercy. "The industry is aware of our position on busting trades, "a company spokeswoman says.-----
My point is, I'm glad they are consistent. The application says, there will be no margin calls, boom, you're liquidated, I'm glad they are as responsible as I am.