I'm using Web form builder with mail chimp and noticed that I am sometimes getting duplicate sign ups by the user. Is there a way to display a message to the user that tries to signup twice letting them know that they're already signed up and to give them to option to update their profile?

The regular mailchimp form does this. I have a website that gets hundreds of signups a day and this extra email we sometimes get from users who sign up twice or even three times causes problems in our workflow.

Any ideas?
Thanks,