Hi Karen,
From what I've seen same name, but different email address (non work, usually a yahoo, gmail or hotmail). They'll be acquired in the program but will be unsubscribed, those are the ones who received the forwarded message. If they're opted in to that program already but are using a different email, I just activate the unsubscribed email, but if it's a totally different person, I'm keeping it unsubscribed for now.
The problem I'm still thinking about is, if they actually opt-in as a result of the forwarded email, they'll be stuck in the unsubscribe status. I just have to watch out for it.
I do want to automate it where if someone gets added to the program by way of forwarded email (this is usually for our newsletters, and podcast/video emails and some promotions), change data unsubscribe from true to false, then send an email to opt-in, and if they unsubscribe, delete from Marketo.