Sending an important email to a contact unsubscribed from all topics

When using {{amazonSESUnsubscribeUrl}} in a template, there is the following option on the subscription preferences page:

This option promises that the contact who is unsubscribed from all topics will still receive important transactional and billing-related emails. How can I fulfill this promise? That is, how do I send an email to such a contact?

I tried not specifying the ListManagementOptions argument to send_email and the unsubscribed contact did not receive the email. Whatever topic I put as the TopicName in ListManagementOptions, he does not receive the email because he is unsubscribed from the topic. I am thinking that there might be a special TopicName reserved for this purpose, but have not been able to find anything to that end in the documentation.

So, how do I send important transactional and billing emails to a contact who unsubscribed from all topics?

P.S. The question at SO