I know people who leave their TV sets on all night long just so there will be "some noise" (their words) in the house or apartment. Are they counted? Who knows?
The PPM, once docked, will stop validating measurement if there is no movement after a certain period of time. But it will begin detecting at some point early in the morning around the average wake-up times to capture any listening when in the dock before the meter is clipped to a belt or a purse. I believe Nielsen TV meters do the same thing if there is no channel changing for more than a certain time.
A lot of TVs and DVRs of more recent construction also go to sleep to rest the screen (even if the DVR keeps recording). All of mine ask "continue to view" after about two hours of no button pushes (mute, volume, channel, etc).
But as I said in my prior post, advertisers have known about this for decades. It's factored in, just like companies "factor in" wear and tear on your personal car if they pay your expenses for business use. It's a known condition and, thus, not relevant to this argument.