First off Hunter, you don't have to get pissed off! I'm not jumping in your ass and I'm NOT saying that ALL guns have to be kept cleared and safe until you want to pull the trigger. Thats really pushing the point way too far. I'm talking about TEACHING here, not carrying as a duty weapon or anything else.
All I'm saying, is that if you are DEMONSTRATING with a weapon, that it is much safer to use dummy rounds than live rounds. Yes, IF you are handling your weapon properly and safely, WHILE DEMONSTRATING, nothing SHOULD go wrong. But, IF you are just demonstrating, why run the risk of accidentally setting off a round? That is just a risk that in a class room setting, is un-necessary and unsafe.
If I'm demonstrating how to change the blade on my Table Saw, I'm not going to do it while it's plugged in. No, it shouldn't start and chop off my fingers, but why take the risk? Furthermore, just because I unplug the saw to change the blades, doesn't mean I have to keep it unpluged until I'm ready to cut a board.
There are levels of risk that are acceptable in a training environment, and levels of risk that are not. Demonstrating loading and clearing proceedures with Live ammunition, is not. It is a fact that the vast majority of accidental or inadvertent discharges happen during loading and clearing proceedures.
You might say WTF, but I say, WHY RUN THE RISK if you don't have to?