The default is silence
Marketing Cloud Growth and Advanced operate on an implicit opt-out model. A contact with no explicit consent record is not mailable. This is the single most consequential difference from Marketing Cloud Engagement, and it is entirely possible to complete a migration without anyone noticing it.
You notice on the first send after go-live, when the audience resolves to a fraction of what it should be. The data migrated correctly. The permission to use it did not.
Consent is keyed to the contact point
In Marketing Cloud Engagement, subscriber status attaches to the Subscriber Key. In the Data Cloud consent model it attaches to the contact point — the specific email address or phone number.
That re-keying is where most mapping errors originate. A migration that carries consent across on Subscriber Key produces records that look complete and enforce nothing, because the consent is not attached to the thing being mailed.
What does not carry across
Three assumptions are worth naming because each is wrong. MCE global unsubscribes do not automatically become explicit Opt-Out records. Publication Lists do not map cleanly onto the new subscription model. And the CRM “Email Opt Out” checkbox is not the same field as Data Cloud consent, though both are visible in the same org and both look authoritative.
Each of these has to be mapped deliberately. None of them will error if you skip it.
Audit before you cut over
The guide includes SQL to audit consent state before migration — how many contacts hold explicit consent, how many are implicit-only, and which contact points will be unmailable on day one. Running it before go-live converts a post-launch emergency into a scoped pre-launch task.
Given the GDPR and CAN-SPAM exposure, this is one of the few migration steps where getting it wrong is a legal problem rather than an operational one. The guide closes with a pre-migration checklist.
What’s inside
- Implicit opt-out wiping your list on day one — the single biggest trap
- Consent is keyed to email and phone, not Subscriber Key
- MCE global unsubscribes never become explicit Opt-Outs automatically
- Publication Lists do not map the way you assume
- CRM “Email Opt Out” versus Data Cloud consent — not the same field
- Contact Point Communication Subscription, explained properly
- SQL to audit your consent state before you cut over
- GDPR and CAN-SPAM implications, plus a pre-migration checklist
