Your ISMS is certified. Your Statement of Applicability covers the controls. Your auditor arrives and runs a DNS lookup on your domain.
dig _dmarc.yourdomain.com TXT +short
The output shows p=none. The auditor makes a note.
This is not a hypothetical. DMARC policy enforcement has become a standard ISMS audit check since ISO 27001:2022...
🛡️ VERIFIED CYBER INTELLIGENCE ID: #3530040