Add a column in the User List report available through User Management and add a checkmark column in the dashboard to visibly call this out.  
We had a user that required a license, however we encountered a violation as the user had an alternate email so it was seeing user as already licensed.
Steps taken:
- Security Admin deleted the user's old email address from our enterprise account -however the new email address had been added as an alternate
- Alternate email remained active, did not get deleted by step 1, Security Admin did not have any visibility into an Alternate email existing for the user
- Security Admin tried to add user with new email address however got an error "A business rule violation occurred. Failed to add user"
- Security Admin contacted Smartsheet for guidance and came to know that the user's new email was active.
- Security Admin invited new email to collaborate
- User setup new account using new email
- Once user completed setup, Security Admin was able to add a member license to the user
Question, what's the expected behavior when a user is deleted and has an alternate email.  I would expect the alternate email is also deleted and remove access to all assets.