The ruling in the Patco Construction vs. People’s United Bank case set precedence, because the judge basically ruled that the bank’s below par security was sufficient for small business — and Patco (small business) was held liable for paying for the fraud that was a result of an average bank security. To know more details of the case, Brian Krebs has written a great post on this case.

http://krebsonsecurity.com/2011/06/court-passwords-secret-questions-reasonable-ebanking-security/

Brian Krebs also wrote about another high profile case (emi v comerica) which was decided in the favor of small business (EMI)
http://krebsonsecurity.com/2011/06/court-favors-small-business-in-ebanking-fraud-case/

Baed on these two cases it is hard to know how the next online banking fraud case will be decided and on which precedence. I guess the courts are still trying to figure out how to decide these complex cases and where to set the due diligence bar for the banks.