That's the second time it's happened in as many weeks. Clearly some people are playing with massive amounts of cash.
Having said that...the market is still larger than one person, so they can still get mobbed...unless that person secretly has about $100m in a gox account ready to go or something.
Is there a way we can guess the max USD any given individual has? Different regulations for holding money over a certain amount or something.
If people are trading with 1% risk on NAV...I suppose you could make some estimates. Very difficult though, I'm sure, and I doubt many people actually adhere to that rule strictly.