When a new account is created an email is always sent regardless of whether email notifications are off. My installation does not require any email notification and so the signup & notification globals are off.

However, in user user_api.php user_create it calls the email_api.php email_signup function which has this code:

Send signup email regardless of mail notification pref

or else users won't be able to sign up

email_send( $v_email, lang_get( 'new_account_subject' ), $t_message );

This should be fixed to honour the email settings, otherwise systems which deliberately do not have email configured get a screen showing the email and smtp errors.

Dave