Concerns are mounting regarding recent actions by the U.S. government, specifically the Customs and Border Protection (CBP), which has been reportedly purchasing location data from online advertising agencies. This information, detailed in a report by 404 Media and confirmed by an internal Department of Homeland Security (DHS) document, indicates that CBP employs a circuitous method to access location data. This data is primarily gathered through various phone applications, including popular video games, raising significant privacy implications for individuals.

By combining this acquired location data with specialized tracking tools, the DHS gains the capability to monitor a device's movements. This extensive tracking could potentially reveal sensitive personal information, such as an individual's residence or workplace. The process through which CBP obtains at least some of this data is identified as real-time bidding (RTB).

Real-time bidding is a sophisticated automated process predominantly used by marketing agencies to determine which users will be exposed to specific advertisements. When a mobile application is poised to display an ad to a user, an instant bidding war commences among various companies vying for that advertising space. During this rapid auction, automated systems, often referred to as 'robots,' utilize data associated with a particular user's phone. This data helps them ascertain the value and relevance of surfacing an advertisement to that user. A common real-world manifestation of RTB is the experience of receiving a highly personalized web banner advertisement, often appearing shortly after a specific search query on a search engine, demonstrating the pervasive nature of this data-driven advertising technique.