On the QuickBooks Export screen there is an additional field called QuickBooks Transaction Type, which has options for Cash Sale and Deposit:
QuickBooks Transaction Type
When the QuickBooks Transaction Type field is set to Cash Sale, the import in QuickBooks will always create a Customer record, even if the Create Customer Records field is set to 'No'. The type of transaction that is created in QuickBooks when Cash Sale is selected requires that a Customer record be set up for the donor.