Questions of mass surveillance aside, I always wonder how useful these things (motion detection when you're not home) actually are given how many American households have dogs and cats.
I wouldn't be surprised if they can't tell the difference between a person and pet. Also wouldn't be surprised if they used that data to push pet food ads at you somewhere or just sold that info to a data broker.
I'm assuming you really meant "detect human motion", which I don't think is a solvable problem at this point in time, at least with high accuracy.