In advance of the Supreme Court weighing in on the subject this fall, a number of top tech firms this week argued that when it comes to law enforcement access to customer cell phone records, "expectations of privacy in the digital age" should outweigh "rigid analog-era rules."

Later this year, justices will consider whether police need a warrant based on probable cause before accessing cell phone location records from wireless carriers. On Monday, a group of tech giants—including Apple, Facebook, Google, Twitter and Verizon—filed a brief with the Supreme Court arguing that the Fourth Amendment, which protects against "unreasonable" searches and seizures by law enforcement, "must adapt to the changing realities of the digital era."

"Rather than adhere to rigid Fourth Amendment 'on/off' switches developed in the analog context, courts should take a more flexible approach that realistically reflects the privacy people expect in today's digital environment," said the group—which also includes Microsoft, Airbnb, Cisco Systems, Dropbox, Evernote, Mozilla, Nest Labs, Oath, and Snap.

"Courts should focus on the sensitivity of the data at issue and the circumstances of its transmission to third parties. That approach would better reflect the realities of today's digital technologies and accommodate the technologies of the future."

The American Civil Liberties Union (ACLU), which is serving as co-counsel in the case, argues that because cell phone location records offer a wealth of private details about people's lives — such as their personal relationships, visits to the doctor, or religious practices — they should be covered by the protections of the Fourth Amendment.

"The tech firms are sending a very clear message that the law needs to catch up with the technology that is now an integral part of our everyday lives," ACLU attorney Nathan Freed Wessler said in a statement.

In Carpenter v. United States, the ACLU is representing Timothy Carpenter, who was convicted of robbery in Detroit, based in part on months' worth of phone location records the government obtained in 2011 without a probable cause warrant. The records covered 127 days, revealing 12,898 separate points of location data.

"Carpenter's call records reveal that over the course of four months, his phone was located in more than 200 separate cell tower sectors," the ACLU said. "These records provide a very detailed accounting of everywhere he went."