In the "form editor" there is the opportunity to set the address field as required. But when user leave it empty he can register anyway. Is this a bug or is there a possibility to make the address fields required, so that have to insert his address?
After you put the address brick in the signup form, click on "Configure" and then check the "Require Address Info" box. Then be sure and click on the "Save" button at the bottom of the page.