Oh Robert my guru,

I admit the fact these guys are idiots makes me suspicious of anything
they say. This particular DIYer said...

"Or, w/ the water supply off, somebody ran some hot water and since
the
heater had no resupply it overheated and blew off some steam during
the
night."

What I thought he was saying was that with the main off, the heater
emptied itself of water which caused it to overheat. The "resupply"
comment struck me this way. If I've been too hard on him, I will
apologize (as all plumbers are quick to do).

Mikey