Honoring opt-outs is not optional. WhatsApp's policies and privacy laws such as the GDPR require businesses to stop messaging anyone who withdraws consent, and to make that withdrawal as easy as the opt-in was.
In practice, businesses handle opt-outs with keyword detection (STOP, UNSUBSCRIBE, and common variants), an explicit button in marketing templates, and a suppression list that removes the contact from future campaigns immediately.
A clean opt-out path also protects deliverability. A customer who cannot find the exit blocks or reports the number instead, and blocks weigh far more heavily on the quality rating than a quiet unsubscribe ever will.
