You may face a situation when neither a routing number nor SWIFT code is required for a payments but sytem required adding it to the bank acocunt because of the following error message: "Neither the SWIFT code nor the routing number is available for the Bank account. Please select Setup › Bank accounts, and then add the SWIFT code and/or the routing number on the General tab for the specified vendor."
Users are forced to enter a routing number or BIC/SWIFT code.