Encourage customers to opt back in

We're a B2B e-commerce and we'd like to run a few marketing activities to encourage our customers to re-subscribe to our marketing communications. From what I can see, even if someone completes our email sign up form after unsubscribing, they will still be blocked on Sugar Market by the "guarded watch list". I can technically opt them back in manually through Sugar support but that means I'd have to be notified that a customer in the watch list wants to re-subscribe. Has anyone come up with a solution to flag anyone who wants to be opted back in?

I wonder why people can't be removed from the guarded watch list automatically if they click on a double opt in form for instance?