I understand all this too. However, I hope (and think) we agree that the microwaves vibrate water molecules, so, if you're right (and I do believe you), where is the water in the electrical components that suffer as a result of being bombarded?

One other thing I can't get straight here - are we really saying that there is so much leakage (billions of waves a second), that having nothing in the microwave doesn't make much difference?

When I think of the energy required to warm a cup of tea in a microwave, I find it difficult to believe that when nothing is there, the whole energy furnished by the electrical supply has just .....gone......

Presumably there is leakage when something is in there too, so something, to my simplistic mind, does not add up.