Greetings. I have 2 questions. First, all advice to drain water heaters always says to turn things off first. I just connect a hose to the drain valve and drain it out under pressure for 5 minutes. Why do you need to turn things off? I've never done this and have never had a problem. Second, let's say you go away and turn off the main water supply and leave the water heater on and untouched. Now, let's say the heater pops a leak. When the water runs out will the heater attempt to heat an empty unit? Will some other damage occur? Also, I've read where if that water in there is not sufficiently heated (people shut it off or turn it down) it could lead to Legionnaire's Disease and/or rusting issues. What's the deal on all of this? Plumbers I've asked seemed puzzled.