The lack of the header should indicate that the user denied consent to be tracked.
I'd rather something that auto-rejected, so I don't use it, but it exists.
This bit is actually the opposite. All tracking _must_ be opt-in, therefore by blocking the pop-up and not opting-in the website cannot track you.
It's only for the websites which are broken when not opting-in that it accepts the policy (which AIUI is itself a violation of the GDPR).
The lack of the header should indicate that the user denied consent to be tracked.