Actually, they can (or at least, they should). The personal settings are divided into categories (pages). There are a couple of settings' pages they can get into (although, maybe with the recent changes in the forum, something went wrong; the admin should double check again the Newbies permissions in that case).
So, they should be able to see their email addresses, but they shouldn't be able to post a signature for example.
Whichever the case, I still think the default setting for emails should be "NO". I guess VLK and Chocholo should decide about potential problems and/or inconveniences for "YES" and for "NO" as defaults for this option.