While the U.S. Supreme Court said police generally cannot follow people through their cell phones, the justices did not prohibit cell phone companies from doing it.
In Carpenter v. United States, the Court said police violated the defendant's expectation of privacy, but most people surrender it as soon as they turn on their phones. In that way, the decision is notable for what it didn't say.
It may trouble privacy advocates, including the four justices who dissented in the opinion, but the law -- like GPS tracking -- only goes so far.
Follow the Phone
Writing for the majority and in a break from conservatives, Chief Justice John Roberts said most people "compulsively carry cell phones with them all the time. A cell phone faithfully follows its owner beyond public thoroughfares and into private residences, doctor's offices, political headquarters, and other potentially revealing locales."
In the government's case, Roberts wrote, it is a "near perfect surveillance, as if it had attached an ankle monitor to the phone user." The Court said the government can't do that without a warrant.
For years, lower courts have struck down police enforcement through cell phone tracking and other surreptitious measures. In Carpenter, the Court pointed out that it was not ruling on traditional surveillance, such as security cameras.
It also left open the issue about how cell phone services and other private companies can track the movements of virtually everybody -- through some 396 million cell phone accounts in the country.
Business as Usual
Cell phone users enable GPS tracking on their phones all the time. Whether they use it to drive, search the internet, find their kids or the McDonalds "near me," they consent to the technology.
Even without consent, cell phones companies and internet businesses "follow" consumers as a matter of course. The Supreme Court said nothing about all that.
Until the next case, businesses and individuals may continue to use GPS guided by others' reasonable "expectation of privacy." You may want to consult an attorney for more.
In case you didn't know it, they may already know where you are.