It would be nice if there was another 'state' you could add members with bounced email addresses to. It should act just like the 'Awaiting confirmation' state as far as giving those users "Guest" permissions, disabling all emails except confirmation emails, and adding a notice letting them know what's going on. The only difference would be that users in that state would be able to change their email address. Right now you can add members back to the 'Awaiting email confirmation (from edit)' state, but for members who no longer have access to the email address they used to register there is nothing they can do because they do not have permission to edit their email address (unless I'm missing something). Also, if they continue to click 'Resend Confirmation' your server will just keep sending more and more bounced emails.