How the Government Uses Advertising Data to Track People (and What You Can Do to Limit It)

"Customs and Border Protection (CBP) is among those buying and using location data collected via ads to track users' movements. Immigration and Customs Enforcement (ICE), the FBI, and a handful of other federal agencies have also purchased location data from brokers in recent years, but the internal document from the Department of Homeland Security obtained by 404 Media confirms that CBP has sourced its location tracking in part from real-time bidding (RTB), which is behind every online ad you are served."

"The app or website pings an ad tech company to figure out which ads to serve, and that company puts together a 'bid request' using your data, including your device's advertising ID, IP address, demographic information, GPS coordinates, and more. That bid request goes out to thousands of advertisers, and the highest bidder is the one that ultimately gets displayed."

"In the meantime, both ad tech companies and advertisers receive all of your data, and organizations that purchase this data can connect movements to specific devices, facilitating surveillance over a period of time."

"Law enforcement agencies in almost every state can purchase location data from data brokers without first obtaining a warrant, so the onus is largely on users to protect themselves against location tracking."

Government agencies acquire personal location data through two primary channels: direct collection and purchases from data brokers. Customs and Border Protection specifically obtains location tracking data via real-time bidding systems embedded in online advertising. When users open ad-supported apps or websites, ad tech companies collect device identifiers, IP addresses, GPS coordinates, and demographic information within milliseconds. This data is packaged into bid requests distributed to thousands of advertisers. Both ad tech companies and advertisers gain access to user data, enabling organizations to track device movements over time. Law enforcement agencies across most states can purchase this location data without obtaining warrants, placing responsibility on users to implement protective measures.

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