I think it's more that no one ever actually boils it. They microwave it to drinking temperature. I'm not sure it would be safe to boil it in a microwave, the water would go everywhere.

Microwaves don't always superheat water. I find that when I'm making an individual cup of tea, it gets superheated far less than half the time, and even when it does it doesn't react violently enough to the introduction of the tea bag to be a concern.

Put a teaspoon in the water - it will boil not superheat. Thought everyone know this :)

Just not a metal one.

Does microwave boiling remove the gasses trapped in the water? It's what makes water taste flat.