It is true --- go and google it. Don't know about existing chargers. But is you have a smart meter in your house already that supplies your charger then that power consumption - rate - time- can tell a lot about what is being used, the smart meter can "tell"-- record when you put the oven on compared to when you put the kettle on compared to when you charge your phone as they all have their own power signatures vs time used - not difficult to work out what is being used - against the background consumption of a fridge. If you have a smart meter installed then congratulations - you have installed a spying device. -- For your convenience.
Oh dear...
Of course, if I got one of those house batteries, that would make it even more fun...

