That is what I originally thought, however in reality it did not work.
I setup numerous smart outlet style devices to alert me if they were turned off. Power went off and NONE of them changed state to OFFLINE or sent notifications through they were OFFLINE. Waited over an hour for notification. Alerts only worked if the outlet was turned off (via direct button press, app on/off, remote, etc). Alerts did NOT work if power went off.
Basically if I can set it up as an open/close sensor it should be very reliable. Finding an available sensor for this that just works out of the box is the immediate challenge.