You can make a separate scan page for new subscribers to your newsletter. After they have subscribed, you can send them a link to this page including their e-mailaddress so it is automatically filled in.

You can show the field (so that your subscribers can enter, change or remove it) of hide it, but do consider manual input for performing scans on other computers.

You can also specify a scan category, so that you can show a specific message for these deze on your own result page.