well, it's one thing to feel insecure knowing that people know where you are (cellphone/mic/GPS). But if you're attacked/ambushed/blackmailed/kidnapped, you can always fight for yourself, scream to attract attention, etc.
It's another thing to feel insecure knowing that people know when your home is unoccupied. Just wait until the next big data breach happens.
It's especially interesting b/c not only is this a "when are they not home" detector, but the "they" is an indicator for "wealthy enough to afford nice things."
Then we make products like the nest that sit in out houses with cameras in them, tie into facial recognition software and alert the police. Or, even better recognize that intruder is not on a white list and owners are not home and use automated home protection to disable them.
Those kinds of situations are the driving force of many thin a: warheads & bunkers and safes & crackers quickly come to mind.
And if the NSA can target a huge company like Google, I bet Nest was child's play to infiltrate.