Do Not Call

The layers operate independently. The US national registry covers consumers who have opted out of telemarketing generally. Some states maintain their own registries with different scope. Internal do-not-call lists record people who asked a specific organisation to stop calling, and that request must be honoured regardless of any other consent on file. Litigation-focused lists of known serial plaintiffs are a commercial risk-management addition rather than a legal requirement.

Timing and freshness matter as much as the check itself. Registry data changes, cached results go stale, and a number scrubbed weeks ago may have been added since. A suppression architecture needs a defined maximum age for cached results and a defined behaviour when the scrubbing vendor is unavailable — because the alternative to a decision made in advance is a decision made accidentally at dispatch time.

Reassignment is the failure case teams overlook. Disconnected mobile numbers are reissued to new subscribers, so consent captured from one person can lead to calls to someone who never gave it. Checking a number against reassignment data before calling is the standard defence, and it is separate from the do-not-call check even though both run in the same gate.

The operationally important property is that suppression is checked immediately before dispatch, not when the list was loaded. A campaign built yesterday and run today must re-check, because an opt-out received in between has to take effect.