"Fool me once," so the old saying goes, "shame on you. Fool me twice, shame on me." It is a proverb memorably flubbed by former president George W Bush in 2006 and one hedge fund managers seem to have taken to heart since September 2008. Following the collapse of Lehman Brothers, prime brokerage clients discovered they had lost billions of dollars of initial and variation margin held by the firm - a fact that evoked little sympathy among a public disgusted with Wall Street.
By November, the scal