Can I Blacklist a Bad Contact?

1. Add a Tag "Bad Contact" to the contact.
2. Create a Campaign that looks for a change in the Bulk Email Status field, with a condition that the change is to "Single Opt In". Have the Trigger apply to anyone in the account.
3. Add a Condition to the Campaign that checks for the "Bad Contact" Tag.
4. On the Yes side of the Condition add an Update Contact element to update the field "Bulk Email Status" to "Transactional Only" (opt out). Add an Exit that removes the contact after the Condition (this element is an End element with the checkbox to remove them from the campaign checked). 
5. On the No side of the condition add an Exit element. 

This will prevent the contact from receiving any more email from you whenever they opt back in. You can add other elements on the "Yes" side of that Condition to remove them from Fulfillment Lists, Campaigns, or anything else you would like.