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frees the user from the wire

is practically zero EMF

tethers the user to the wire

is practically zero EMF

tethers the user to the wire

good transformers are low EMF; bad ones emit unwanted EMFs

If vendor uses solar meter to measure LED power density, the real value is less than half the claimed value.

If vendor relies on manufacturer's power density claims, the real value can be significantly less than stated.

Power density at zero inches (light pressed to skin) is reliable if tested with a spectrophotometer or LED meter, HOWEVER

Power density measured at any distance is vastly overstated due to reflectance. 

For example, if you measure power density at 6 inches with a meter designed to measure LED light, and get 100 mW, then you can say that 100 mW lands on the target surface. But because the skin REFLECTS photons, and because the lamp is not pressed to the skin to blunt reflection, that 100 mW value is drastically overstated. It can be and often is as low as 5 mW/cm^2 when stated as 100 mW/cm^2. 

Therefore, a LOW to NO EMF light pressed to the skin is signficantly more powerful than a "powerful" light at 6 inches.