Email addresses are displayed when you search for users in the edit page restrictions page - even if Confluece is set up to display emails only to admins. User has to have "restrict" + "create" permission to be able to access the user lookup.

How to reproduce:
Log in as a regular user (without admin privileges). Go to a page, click Edit, scroll down to "Restrictions". Click on "Choose users" and enter some string.

Result:
Users are listed with their email addresses displayed.

Expected Result:
List of users with emails hidden.