"If a user likes me enough to forward my newsletter to 60 of their friends and one of them -who also happens to be subscribed to the same newsletter-" No, the

"If a user likes me enough to forward my newsletter to 60 of their friends and one of them -who also happens to be subscribed to the same newsletter-" No, the people the user forwarded the email to are not subscribed. You have misunderstood the scenario.