At issue, for SCOTUS to decide, is the third-party doctrine, which says, if you hand your data (e.g. your location) to a third-party then you shouldn't expect it to remain private.
One of the most read pieces on this blog, with over 100,000 page views, is a post about Facebook privacy. Then, I discovered that Facebook was keeping track of me via breadcrumbs. Would you like to see if Google is also keeping tabs on you? Then visit history.google.com.
Litmus TestFor tomorrow's case, Orin Kerr submitted a brief on behalf of the government arguing that the Fourth Amendment doesn’t protect location data because it’s the equivalent of being observed in a public space.
I think Kerr's argument falls short because this data allows us to be observed in private spaces, too.
My litmus test is: how would this apply to the POTUS? Most of us would agree that we shouldn't expect privacy, in the case of a video surveillance camera recording us, in public. If the President walks down a street in New York City, many cameras will record him. But, shouldn't the President's exact location be private, in private? Did the President tweet from the Oval Office, his bedroom, someone else's bedroom, or perhaps a bathroom? Cell phone location accuracy using GPS, WiFi, Bluetooth, etc can be accurate to within a few meters.
The current challenge is that technology is evolving so quickly that consumers don't fully understand how they unknowingly yield their privacy, and laws have not caught up with citizens' expectations or understandings.