🚫 Message Suppression List — your "Do Not Message" list
Keep a global list of people you never want to message. Add them by hand, paste a bunch at once, or import a CSV. Every broadcast then automatically skips anyone on the list — they'll never get a message — and shows a "Suppressed" badge next to them in the Skipped list, so you always know who was held back.
Find it under Messaging Tools → Suppression List.