The default email preference to set the email transaction field in the customer record is set as true in the navigation Setup>Company> Email Preference> CUSTOMERS DEFAULT TO EMAIL TRANSACTIONS.
So new customers created will have this check box automatically ticked.
Using workflow we can untick the email transaction check box as per our requirements.
For Eg: Create a new workflow for untick the email transaction checkbox for the new creating Australia subsidiary records( lead, prospects, and customer).
If we create a customer record for the Australia subsidiary, then the workflow trigged. If the email transaction check box is ticked then the email transaction check box is unticked automatically using the workflow.