Which switch did you order, Dave? I was thinking about this the other day. I turned off the stove on Sunday, and after unplugging it, the fire died FAST since there is no draft at all with a direct vent.
I can imagine a short power outtage at 8am after leaving for work and coming home at 5pm to an ashpan full of coal. Having a failsafe control to shut the stove down would be really nice. It would just require an override switch to allow the stove to be started and come up to temp and make the thermostat.