Wireless Power- ANSWER

This is not trick photography!

I pulled the power cable out and the light stayed on for about 2 minutes afterwards. The reason?

The circuit inside the black box contains a large capacitor, which stores electric charge. This can be discharged quickly by putting a metal screwdriver across the pins of the plug, or left to trickle slowly away as the moist air conducts the charge to ground.

Lima, Peru, 17/04/2008