[development] user account email required?

When an admin edits a user's account, say to add a role, and then tries to save the result, the form requires that an email address be entered. Yet the database itself does NOT require email addresses. If one is using something like LDAP or other alternative authentication methods, the email field is often blank. So now the admin is out of luck because she can't update the record, as she doesn't know the email address. I believe this should be changed to remove the requirement for an email address to be present. Is there some reason why it needs to be this way, or to not create such a patch? ..chrisxj