Word of mouth from Boing Boing Saturday night: Citibank customers traveling out of the country have been frozen out of their bank accounts. They are being told that the ATM networks of Canada, Russia and the United Kingdom have been "compromised", so that using an ATM card over the Canadian network locks out your account automatically.
"She informed me that I would have to return to the United States to change my pin number before my card would be valid and in a usable state again. When I informed her that I would be traveling outside of the United States for at least a few months, possibly up to six, she repeated that I would have to re-enter the United States to fix the problem."
Electronically frozen assets have been a trope in science fiction at least since Heinlein-- that's why so many of his characters have gold stashed somewhere. In Margaret Atwood's "The Handmaid's Tale", electronic banking was used to strand the opposition and take over the United States.
Gotta wonder is this isn't criminal activity at all, but a dress rehearsal for some future "state of emergency". I hate being intuitive sometimes. I still remember puzzling over a small NYT story about an assassination in Northern Afghanistan the weekend before September 11, and thinking that the murder reminded me of the prologue for a paperback thriller...