You will see the designation “confidential” on class rosters for these students.
Faculty and staff may still contact the student regarding class business, but should avoid releasing any student information, including email address with any one else (including other students).
Students with the confidential indicator should be not included in group e-mails to your class in a way that shares their email (Bcc all group emails).
A student may have many reasons for applying this hold, including reasons related to personal safety, so it is important to avoid any inadvertent release of student information.