RCM's automations have the option to add conditions to each task. Once an automation has been triggered, the task will only run if all the conditions are met. 

There is now a Mailing List condition, which means an event will only be run if the customer either is or isn't on the Mailing List

To apply this condition, open up an Automation Task, go to the Conditions section and select "Add Condition". the click on the first drop down bar that appears.

This will open up a list of placeholders. Select the Mailing List option under Hirer.

Then, in the drop-down bar beneath, you can set this condition to YES or NO.