It is very important to have the MAC address added to the Azure AD user sign in report to know which devices are connecting.
In order to audit whether a permitted device is accessing a user account we need to be able to uniquely identify the devices connecting to the user account. By adding the MAC address of the device connecting to the tenant we can isolate all devices that are accessing the data. This is different from the devices that are listed in the tenant as installations. A non-authorized user could be accessing a user account if the password has been jeopardized by adding the email credentials to any email client or by accessing the portal directly. Adding the MAC address to the Azure Active Directory User login report would enable a more complete audit.