More background: In that particular case, the password of an account was obtained on the customer's computer (a keylogger or a phishing attack targeted at the c

More background: In that particular case, the password of an account was obtained on the customer's computer (a keylogger or a phishing attack targeted at the customer directly), as opposed to the bank's network being attacked and the customer chosen at random. Basis of the ruling was that the bank could have prevented the attacker from withdrawing money, which could have been flagged as suspicious, but it was up to the customer to protect his account, not the bank to act as guardian to every customer. In regards to this MtGox issue using the same argument, if it is known that an attack did happen, an that attack was directed at MtGox directly, then yes, they should roll back that trade because someone is out money/BTC due to an attack that could not have been prevented by that account holder. The only way to legitimately know who is responsible for the sell off is to be transparent, however, it seems that MtGox hasn't fully released details of the incident and we are all speculating on what exactly happened.