"Geofence warrants are just part of day-to-day cop business these days," laments Tim Cushing at Techdirt. "Rather than moving forward with a list of suspects, law enforcement agencies just ask for data on everyone in a certain area at a certain time and move backwards to probable cause to investigate and arrest."

The FBI utilized geofence warrants in its investigation into January 6 protesters—one of whom challenged the use of these warrants in court, filing a motion to suppress data obtained through the warrant.

A court has now denied the motion to suppress. "The ruling [PDF] from the DC District Court does have a few problems with geofence warrants generally, but not this particular one," notes Cushing. "The court also says there's no expectation of privacy in anonymized location data. Referencing the Supreme Court's Carpenter decision, it says hoovering up massive amounts of data related to hundreds of devices isn't the same thing as harvesting data targeting a particular device over the space of days or weeks."

Cushing has more on the decision and on what it means here.