Yes, that's been suggested before. I think it would be a good option to offer. In the meantime, you could set the PC to Sleep after some period of inactivity, which will at least reduce the power draw.
Problem with that is I got a computer that hates sleep or Hibernate modes It never wants to wake up it likes to play dead. So I disable Sleep & Hibernate modes on this computer.
I was thinking about adding "if your PC can handle Sleep or Hibernate mode" in my reply... I've got a few PCs with that issues. In fact, my wife's PC will randomly crash if you even enable Sleep and it will never sleep on its own.