By default, when a user is logged into a device and walks away, and comes back to it when the screen wakes up it will assume the same user is using the same device.
This is a fair assumption if the device is only used by that user, however, if it is a shared device you can set an option to have it log out after 15 minutes. So then when the next user picks it up, there will be no logged-in user and they will have a message saying "please open the app and start a session".
You can set the "shared" device option on the device record, via manage.myscreencoach.com
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