Banks are required to maintain insurance coverage, based on an analysis of risk, so when the examiners come in they ask for a copy of all insurance coverage, e.g., D & O specifically, and expect to receive the Financial Institution Bond and General Liability policies. If you don't produce coverage, like the Financial Institution Bond, you are placed in the position of explaining your analysis of the risk with the result that no coverage is necessary. That means that you do not have exposure to employee dishonesty, loss of a cash letter is transit, Fraudulent Mortgages, Counterfeit Checks, Stop Payments, Check Kiting Fraud, Unauthorized Signatures, Forgery or Alterations, On/Off Premises ATM's, etc., etc.
Have you prepared "winning" talking points, supported by an analysis of risk? One big loss can bring down your bank, so coverage is necessary, if not required.