I’m not sure whether you are familiar with the concept of “dying gasp” but it would be very interesting to have it on the BR/MAX/balance devices.
It is used in DSL for example when the power is lost, a last signal is sent to mention to the other-end equipment that the device is powering off and that it is not simply the line that is cut. It helps a lot to avoid false alarms as you know that it is not due to physical layer issue but simply the user powering off his device.
Example: an HD4 could send a last message saying to incontrol that the device is shutdown. Instead of displaying “device offline”, we could then have “Device offline (power)”.