This wikipedia article explain the actual problem with stand-by power consumption:
"Standby power, also called vampire power, or phantom power, refers to the electricity consumed by many appliances when they are switched off or in standby mode. The typical power loss per appliance is low (from 1 to 25 W) but when multiplied by the billions of appliances in houses and in commercial buildings, standby losses represent a significant fraction of total world electricity use. According to Dr Alan Meier, a staff scientist at the Lawrence Berkeley National Laboratory, standby power accounts for as much as 10% of household power-consumption. A study in France found that standby power accounted for 7% of total residential consumption; while further studies have put the proportion of consumption due to standby power as high as 13%.
The IEA estimates that standby produces 1% of the world's CO2 emissions. To put the figure into context, total air travel contributes less than 3% to global CO2 emissions."