A new investigation has revealed a troubling reality: U.S. government agencies have been tracking people’s locations using data from online advertising systems—without a warrant.

According to documents obtained by the press, agencies including U.S. Customs and Border Protection leveraged data collected through real-time ad bidding to monitor phone movements across the country.

It’s a practice that raises serious concerns about privacy, legality, and how much of your personal data is silently shared every day.

The Hidden System Behind Location Tracking

The tracking method relies on a little-known mechanism called real-time bidding (RTB)—a core part of the digital advertising ecosystem.

Here’s how it works:

Every time an ad loads in a mobile app:

• Your device sends a bid request
• This happens in milliseconds
• The request is broadcast to thousands of potential advertisers

That request can include:

• GPS location data
• Advertising ID
• IP address
• Device type
• Inferred interests

👉 Crucially, all participants receive this data, even if they don’t win the ad auction.

This means your location can be shared with hundreds or thousands of companies daily, often without your explicit awareness.

Data Brokers Exploit the System

Companies known as data brokers take advantage of this system by posing as advertisers.

They collect massive amounts of data from RTB streams and resell it.

One example is Mobilewalla, which reportedly gathered data on over 1 billion people. According to the Federal Trade Commission, around 60% of that data came from ad bidding systems.

Another major player, Gravy Analytics, was involved in a data leak exposing location data linked to thousands of apps.

These included:

• Candy Crush Saga
• Tinder
• Grindr
• MyFitnessPal

Even apps tied to sensitive topics—like religion or pregnancy—were part of the data flow.

In many cases, developers were unaware their apps were contributing to this ecosystem.

Government Agencies Have Been Buying This Data

Between 2019 and 2021, **U.S. Customs and Border Protection ran a pilot program to test whether advertising IDs could be used to reconstruct people’s movements.

Other agencies followed suit:

• Immigration and Customs Enforcement (ICE)
• Federal Bureau of Investigation (FBI)

They purchased location data from broker Venntel, using it to identify individuals—including undocumented immigrants who were later arrested.

ICE also used a tool called Webloc, capable of tracking millions of devices daily and enabling location-based searches.

Growing Political Backlash

The revelations have sparked concern among lawmakers.

In March 2026:

• 70 U.S. legislators called for an official investigation by the Department of Homeland Security’s inspector general

At the state level:

• Montana became the first to ban government agencies from purchasing sensitive data that would normally require a warrant

At the federal level:

• A bill led by Senator **Ron Wyden passed the House in 2024
• But it failed to pass the Senate

The legal framework around this practice remains unclear—and largely unresolved.

What Apple Did (And Why It’s Not Enough)

In response to growing privacy concerns, **Apple introduced App Tracking Transparency in 2021.

This feature prompts users with:

👉 “Ask App Not to Track”

The impact was significant:

• 96% of U.S. users opted out of tracking
• Advertising identifiers were effectively disabled on most iPhones
• Studies showed a decline in financial fraud among iPhone users

However, this doesn’t fully solve the problem.

👉 Even without an advertising ID, RTB systems can still transmit location and device data.

Android Users Face a Bigger Challenge

On Android, users can also disable advertising IDs—but the process is less visible and less widely adopted.

Privacy advocates like the Electronic Frontier Foundation recommend:

• Reviewing app permissions regularly
• Limiting location access to “while using the app”
• Avoiding unnecessary location-enabled apps

The Bigger Issue: A System That Never Stops

The core problem isn’t just tracking—it’s the system itself.

Real-time bidding operates continuously in the background:

• Sharing data
• Feeding brokers
• Powering surveillance

Even if users opt out of tracking, the infrastructure still exists—and still distributes sensitive information.

Conclusion

The idea that government agencies can buy location data—without a warrant—highlights a major gap in digital privacy protections.

While companies like **Apple have taken steps to limit tracking, the broader ecosystem remains largely intact.

And as long as real-time ad bidding continues to operate the way it does, your location data may still be circulating far beyond your control.

In today’s digital world, privacy isn’t just about what you share—it’s about what’s shared for you.