The unfolding debit card scam that rocked Citibank this week is far from over, an analyst said Thursday as she called this first-time-ever mass theft of PINs "the worst consumer scam to date." Wednesday, Citibank confirmed that an ongoing fraud had forced it to reissue debit cards and block PIN-based transactions for users in Canada, Russia, and the U.K. But Citibank is only the tip of the iceberg, said Avivah Litan, a Gartner research vice president. The scam -- and scandal -- has hit national banks like Bank of America, Wells Fargo, and Washington Mutual, as well as smaller banks,...