You may not realize it, but the cell phone in your pocket creates a time-stamped map of everywhere you go: where you shop, where you receive medical care, and how often you frequent a church, school, or gun range. That's because cell phones automatically connect to the nearest cell phone tower, and by doing so, constantly determine and record the user's location.

WIRED OPINION ABOUT Andrew D. Selbst (@ASelbst) is a postdoctoral scholar at Data & Society Research Institute and a visiting fellow at the Yale Information Society Project who researches law and technology. Julia Ticona (@JuliaTicona1) is a postdoctoral scholar at Data & Society Research Institute who researches technologies of work, inequality, and culture.

Today the Supreme Court will hear arguments in Carpenter v. United States, a major Fourth Amendment case that questions whether the police can access your phone’s location data without a warrant. The government argues that it should always be entitled to that information, no questions asked, because the 95 percent of American adults who own cell phones choose to give up that information “voluntarily.” Because cell phones transmit that data automatically, however, cell phone users have no choice in revealing their location. Therefore, the only action that could be “voluntary” is owning or using a cell phone.

The problem is that cell phones are no longer meaningfully voluntary in modern society. They have become central to society’s basic functions, such as employment, public safety, and government services. The cell phone is a revolutionary technology, but its real value comes not from its technical capabilities, but from its near-universal adoption.

Whether you have a job or are looking for one, there’s a good chance you need a cell phone. If you work in an office, you’re familiar with the demands of work email. But low-wage workers are often even more dependent on phones. Many hourly jobs use on-call scheduling, a practice that requires employees to call in to their workplace several hours before a shift starts to find out if they’re needed. Up to 90 percent of retail workers are subject to last-minute scheduling changes, which functionally require that workers have a phone within reach at all times. Many workers at large-scale retailers like Starbucks, McDonalds, and Old Navy use apps to trade and schedule shifts.

What's more, cell phones are crucial for finding employment. More than half of job-seekers between ages 18 and 29, and 40 percent of 30- to 49-year-olds, have looked for work using their smartphones. The leading job recruiting websites report that most of their traffic comes from mobile devices; 60 percent of Indeed.com’s 200 million unique visitors per month are using their phones to check out listings on that site.

Cell phones are also an important public safety tool. Federal and local governments use mobile alerts to push information out about threats to public safety, missing children, and dangerous weather.

After Hurricane Harvey damaged emergency call centers and the 911 system was overloaded with requests, Houston residents turned to social media sites like Facebook and Twitter for help, primarily via cell phone. Social media use was so common at the time that the US Coast Guard tweeted to remind people that they should still report emergency assistance needs through 911. And when hurricanes Irma and Maria destroyed Puerto Rico’s wireless networks, the hunt for cell phone service caused traffic jams on the sides of highways and packed parking lots outside of hotels. In fact, even outside of natural disasters, 80 percent of 911 emergency calls are made by cell phones.

Government at all levels increasingly relies on cell phones to provide important services. The federal government made big investments to create mobile apps and mobile-optimized websites for its food stamp program, for managing social security benefits, and for accessing US Citizenship and Immigration services. Citing the 12 percent of Americans who rely exclusively on their mobile phones for access to the internet, the bipartisan Connected Government Act, which would require federal agencies’ public-facing websites to be mobile friendly, is currently making its way through the House and Senate.

Major cities such as New York, Boston, Philadelphia, Chicago, and Los Angeles have mobile apps where residents can submit 311 service requests for city maintenance issues like potholes and graffiti. The mobile app NYC Votes lets New Yorkers register to vote and monitor their registration status.

Cell phones are especially crucial for some of the most vulnerable in society. Younger, lower-income, and non-white Americans are particularly likely to own smartphones, but not have broadband in their homes. Smartphones are a cheaper on-ramp to essential services than a laptop and home broadband services. A recent study found that for smartphone users in low-income households, 63 percent report mostly using their cell phone to go online (versus only 21 percent of high-income users). Despite meager resources, homeless people often make cell phones a priority because they are necessary to access critical services and maintain social ties.