We use a generic 'cash sale' account. Obviously not linked to a particular customer, just 'cash sale'.
Problem I have found since the business verification and inclusion of secure payment function.
When 'cash sale' invoices are emailed, even after removing the body of the auto generated message, the recipient gets an option to 'view unpaid invoices on your account'.
This is not ideal, as the other invoices which may be open on the account likely do not belong to that particular customer.
It would be great if we could turn this function off in cases like this when needed, as it is really a security problem.