Skin is quite good at not letting sunlight through, but it's not as good at shielding RF.

Skin is translucent (at least for certain ethnic backgrounds). The heat gets in.

Have you ever gone out on a hot day and stood in the sun? There's a big difference between sun and shade. A head with black hair gets super hot, aside from the general heat you feel.

Another way to say it is 1 kilowatt per square meter. It's a lot of energy. A 1500 watt electric heater can get my entire bedroom quite a bit hotter than with just the central heat running. Put 2/3rds of that energy into your body and there are certainly going to be effects.

Yeah, but I think it's a reasonably safe level for power transmission through corridors where there's not supposed to be any people.

Sunlight is spread-spectrum. This is focused at the frequency that makes water molecules vibrate - which is why we use it for ovens.

Microwave ovens are not "focused at the frequency that makes water molecules vibrate".

This is an urban myth.

http://www.schoolphysics.co.uk/age16-19/Wave%20properties/Wa...

Microwave ovens operate at 2.45 GHz because of frequency management issues - we just can't afford to have jammers all around the spectrum. The first water absorption peak is actually at 22ish GHz.

Any heat which is absorbed causes water molecules to vibrate. Including sunlight. There's nothing particularly special about being broad vs narrow spectrum in this case.