Yes, it is true. This is known as ghost power or Phantom power. It happens when you turn off your television or music system, or switch to the box using a remote control. It also happens when you simply shut down your PC, but not turn off the switch or connect the chargers but no longer connected else with switching them On.Today there are a lot of devices that which fall into this category. Even manufacturers design them to cut down on power consumption in standby mode. But it’s not zero. They draw a small amount of power that ranges from 0.1W to 2W , depending on the systems. They are used by the standby housekeeping system that runs clock, is ready to turn on, wake-on circuits, retention circuits etc.
For a single TV or PC it’s not much, but when you consider a PC, TV or STB, or one or two laptop chargers, and a laptop in the home. The amount of wasted energy can be as low as 1-1.5W. In a typical apartment where there could be more than 100sW that are being wasted. There are some places where this wasted energy is a problem and electricity is in short supply. These areas can be lit by a hundred or two 2W LED bulbs.