GMI section not completed on by mail app

Say we have a by mail application and the GMI box is not completed. Should the bank assume that the customer did not have to provide the information and check the “I do not wish to furnish this information” box? Should we leave it blank, since there is no requirement for us to collect it on a by mail app? I'm thinking of leaving it blank, because the by mail section is marked off. I think that would be self explanatory, but wanted your input.

Thanks in advance

If the borrower doesn't mark it on an application taken by mail, fax or internet, then you leave it blank...even if the borrower is your brother.