Public sessions can be configured to log out when the device is idle for a certain time period. First, a dialog appears warning the user that the device will log out soon:


    === You'll be signed out in 20 seconds ===

        For security, sign out when your
        computer isn't being used.

This doesn't make quite as much sense in public sessions, where a user isn't "signed in". In particular, in Demo Mode, we should have specific text.

Olga, please provide guidance on strings, but I'd suggest something like:

    === Restarting demo session in 20 seconds ===

        [[Something useful here]]