> Just because the header is set, it doesn’t mean it’ll do anything
But they can track proxy metrics for this. For example people using GMail's builtin unsubscribe feature more than once with the same unsubscribe link for different emails is a pretty good indicator the unsubscribe did not work.
But they can track proxy metrics for this. For example people using GMail's builtin unsubscribe feature more than once with the same unsubscribe link for different emails is a pretty good indicator the unsubscribe did not work.