I'f I've got millions riding on a given strike price, and it only costs me thousands to move the price where I want it ....
I think the bank that would issue such options - or anybody who would buy it "against" you - would be fools to accept it for any amount exceeding the hourly volume of MtGox.
Your counterparty is unlikely to be one person. It's the aggregate of everyone that took the opposite position. Either a punter who went naked on leverage, or if there were no sellers for your buys, then the broker would (should) have hedged the position.
What people ought to do, and what people do... two different things!
People do stupid stuff all the time, I'm certainly not exempt from that!
