It is best to assume that global moderators have access to your email, and that admins has the authority to know your email even if you do not make a report.
if you read privacy page you will find that email Retention is Indefinite
I'd be inclined to believe that because the email addresses are stored in a MYSQL database along with the report contents, that only admins are able to read them, as they have direct access to the DB.
Global mods I'm not so sure. But given that these merely are given mod powers in all boards by SMF software, I don't think they have access to the DB either - to give such an access would be catastrophic to security anyway, and it reflects in the security bounty rewards for gaining access to the two types of account.