I read the article and have two questions:
1. Since when can you unplug a furnace? I have never seen a plug and cord-connected furnace, even a gas one.
2. Aren't furnaces usually on their own circuit?
OK, maybe a third question:
In light of my question #2 above, should this guy have even been touching a furnace if he assumed that killing power to a nearby receptacle would shut off the power to the furnace?
I say book 'im Danno.