Who has been swimming naked?

“You only learn who has been swimming naked when the tide goes out…” – Warren Buffett (letter to Berkshire Hathaway shareholders in FY2007)

P/S Full quote: “As house prices fall, a huge amount of financial folly is being exposed. You only learn who has been swimming naked when the tide goes out – and what we are witnessing at some of our largest financial institutions is an ugly sight.”