"To put the Swiss franc move in perspective, in the currency cross rates for free-floating major foreign exchange currencies — like the Swiss franc or the U.S. dollar, the euro or the British pound sterling — a 2 or 3 percent move would be considered big. A 20 percent move is outlandish, a freak black swan event without precedent."

It's not a black swan event if it was predicted, widely, well in advance. Smart, reasonable people declared the policy unsustainable from day one. One good example being Mike Shedlock at globaleconomicanalysis.blogspot.com.