So I just got hold of a few of these new battery chargers from Apple and I'm just wondering if these are meant to stay plugged in the wall, even after the green light goes off. Does the light going off mean that the batteries will no longer draw power from the power outlet and that it is safe to assume power will continue to be consumed? Or is it preferred that I plug and unplug the charger only when needed to avoid any, unnecessary, extra power consumption? Anyone have an idea? Much appreciated, thanks.