Need to add user initiated check box to opt-in for Mailchimp

Mailchimp system compliance just emailed me to say that they noticed that completing my registration process automatically sends a confirmation and subscribes the newly registered user to my mailchimp list. They said that this is a problem if an individual wanted to create an account and did not want to be opted in to my list.

They said I need to update my registration process by adding a blank, user initiated check box so contacts can have the option to opt in to my newsletters at registration (before an opt-in email is sent).

Is there an easy way to accomplish this or should I submit a feature request?

I'm running WP 3.2.1, BP 1.2.9 (preparing for upgrade but not yet ready), Mailchimp Sync 1.1.2, and Membership 2.1 beta 2 (registration form is here).