It seems that the definition of member includes anyone who has registered on your publication (both free/paid).
My question was, what if a member was a paid user in the past but has subsequently cancelled. Will they be counted as members when Ghost Pro calculates how much I pay for the Pro service. From the support team, the answer was “yes” unless I manually delete them as a member from the portal.
Is there any easy/automated way of deleting members when they don’t have a paid subscription anymore. I don’t intend to have a free tier on my site.