[Steven Zahm]

Yes, an email is required. You can avoid the trouble by redirecting to the admin directory profile page rather than using Form. The intent with Form is to accept directory submissions from site visitor, not users. This is why you do not see more synergy between Link and Form, they were designed for two different distinct purposes. Many other users are doing what your doing which is why the next update to Form will be Link aware and allow adding/editing of a users entry using Form in the frontend rather than having to visit the admin page. Right now, the only way to make Form require an email is to edit it so an email field is ready to to accept input without having to click the add button.