Your TV is watching you in way worse ways than that
They track data on target audiences, what you watch, what type of stuff your interested in, and how to tie that in with ads and stuff. They put that into statistical mappings and sell the data and you've got this big mesh of what's going on in the societies mind - all these different subgroups and how they relate. Trends forming, rising, falling. How one falling relates to another one rising
Google knows of outbreaks before the CDC does. They can tell quickly from the spike in numbers of people searching for the symptoms.
I have had tape on my laptop camera for years - but I'm still being watched in a whole other way