🚫 Message Suppression List — your "Do Not Message" list
You can now keep a global list of people you never want to message. Add them by hand, paste a bunch at once, or import a CSV. From then on, every Broadcaster and Mass Messenger campaign automatically skips everyone on the list — they'll never receive a message — and shows a "Suppressed" badge next to them in the Skipped list, so you can see exactly who was held back and why.
Find it under Messaging Tools → Suppression List.