Technology is Turning Immigration Detention into an Invisible Leash

Mariela crossed into Arizona just after dawn, her daughter Isabela pressed tightly to her chest, both of them shivering despite the desert heat rising around them. She was 35 years old, with deep lines etched around her eyes, not from age, but from years of waiting: waiting for her asylum claim to be processed in Guatemala, for her brother’s remittances from Houston to arrive, for the violence in her town to stop.

Border Patrol picked them up near Nogales. Mariela had practiced sharing what happened to her: how she had fled after refusing to pay the gang tax that tripled when they learned she was receiving dollars from the north. She asked for asylum then and there, clutching Isabela as a translator fumbled her words in a language she had never spoken.

Mariela and Isabela were separated that night. “Just for processing,” the officer said. It was 24 hours before Mariela saw Isabela again, but time twisted inside the cold, metallic box they called la hielera, the icebox. Fluorescent lights flickered overhead. The floor was concrete. The mylar blanket rustled like plastic leaves. She could not sleep. She could not cry. She could not think until she was reunited with Isabela, who was catatonic from fear.

From there, Mariela and Isabela were moved to a privately-run family detention center in Texas. Mariela had no idea what that meant. The facility looked like a warehouse. Cameras tracked her every movement, and a heavy bracelet was clasped to her ankle. It buzzed softly every few hours. She later learned it logged her location, steps, and even patterns of restlessness at night.

Every call to her brother cost nearly a dollar a minute. Medical care required a request, followed by a long wait. Isabela developed a cough that would not go away. Mariela began hiding extra food in napkins for Isabela to eat later, hoping it wouldn’t make her daughter sick.

Two weeks later, a caseworker told her she qualified for the Alternatives to Detention program run by Immigration and Customs Enforcement (ICE). She was fitted with a new ankle monitor and released, but she didn’t feel free. A case manager explained how to check in through an app called SmartLINK, which would use her phone’s camera to scan her face. “Just once a day,” they said. But the app sometimes asked three times, sometimes 10. If she missed a scan, she feared deportation.

In her brother’s small apartment in Houston, Mariela set alarms for SmartLINK check-ins. She stopped taking Isabela to the park in case the monitor sent the wrong signal. One night, she woke in a panic, convinced the app had recorded her face incorrectly. Her phone had died. She cried silently so Isabela wouldn’t hear.

Even though she was no longer in physical detention, Mariela’s freedom existed within the boundaries of an app. Mariela didn’t call this surveillance. She called it la cuerda invisible, the invisible leash.

Beyond the rhetoric of “alternatives”

Mariela’s story is a composite drawn from real accounts of people caught up in increasingly digitized immigration detention, as explored in a new report released on September 16, 2025 by the Kaldor Centre for International Refugee Law at UNSW Sydney, International Detention Coalition, and York University’s Refugee Law Lab. The report examines the rise of digital technologies in immigration enforcement like ankle monitors, GPS-enabled watches, and biometric reporting apps, tools marketed by some countries as so-called “alternatives to detention” when in reality they are alternate forms of detention.

On paper, the promise is compelling: technology that allows people to live in the community while their cases proceed, supposedly more humane and cost-effective than physical detention. In practice, however, our research with 158 stakeholders across eight global regions reveals a different picture: these technologies often replicate detention in digital form. They restrict liberty, undermine dignity, and produce profound psychological stress. Instead of dismantling detention systems, they expand them, turning homes and neighborhoods into sites of surveillance.

The rhetoric used by the countries that use these technologies obscures this reality. When surveillance tools are imposed by default, they become detention by another name, or an alternate form of detention.

Three faces of technology in immigration detention

To make sense of these trends, our report distinguishes three categories of technologies used in the context of immigration detention:

1. Surveillance technologies: Continuous monitoring tools like GPS ankle monitors or apps that log location data around the clock. These are the most intrusive, effectively extending detention beyond the walls of a facility.
2. Digital reporting tools: Check-in systems that require active participation, such as scheduled video calls, PIN codes, or biometric scans. Less invasive than continuous monitoring and in person reporting when designed with adequate safeguards, these can nonetheless become coercive when check-ins are frequent, unpredictable, or rely on sensitive biometric data.
3. Digital support services: Tools designed not to control but to assist, such as case management platforms, service directories, and secure communication channels that connect people to lawyers, social workers, or medical care. When co-designed with affected communities, these tools can build trust and promote integration.

The problem is that some governments have embraced surveillance as the starting point, rolled out digital reporting tools without adequately examining their human rights impacts, and underinvested in, and sometimes downright undermined, digital support services.

The Harms of Digital Detention

“It soon became clear that the technology attached to my ankle was pretty glitchy. One time, they came and told me, ‘The system says the tag had been tampered with’. They checked my ankle and found nothing wrong. It sent my mind whirring. What had I done to jolt the strap? I suddenly felt anxious to leave the house, in case I knocked it while out somewhere. I began to move through the world more carefully … My world contracted, and my mental health went into freefall. I came to realize I wasn’t really free: I was in an outside prison. The government knew where I was 24/7. Were they really concerned I would abscond, or did they simply want to intrude on my life?”

– Sam, who came to the UK as a refugee when he was a small child and has lived in Britain ever since, as Coda reported. Sam has been subjected to 24/7 surveillance with a GPS ankle tag while facing deportation.

People who have survived surveillance technologies describe its harms vividly. For example, Sam spoke of the stigma of ankle monitors, which visually mark people as criminals in their communities. They described the anxiety of random check-ins and the fear that a missed biometric scan could trigger deportation proceedings. Others spoke of isolation, choosing not to attend school, church, or work for fear of triggering alerts.

Psychologists warn that constant monitoring can cause long-term trauma, compounding the very harms detention is known for. And while these technologies are framed as temporary, many people are enrolled indefinitely, with little clarity on how to challenge their conditions or exit the programs.

The harms are not only individual but systemic. By normalizing surveillance, these tools entrench a logic of suspicion: shifting the burden onto people affected by detention to prove their compliance through constant monitoring rather than recognising and supporting their capacity to engage with legal processes on their own towards case resolution.

Who profits from the invisible leash?

Another troubling dimension in the increasing role of technology is the role of private companies. Many digital detention tools are designed and operated by for-profit contractors. In the US, for example, BI Incorporated (a subsidiary of private prison giant GEO Group) manages ICE’s SmartLINK app and electronic monitoring programs. Contracts are structured with per-person payments, creating financial incentives to expand enrollment rather than minimize it.

This dynamic of profit-driven surveillance outsourced to private actors undermines accountability. When technology companies hold sensitive biometric data and determine how compliance is measured, oversight becomes patchy at best. People on the move rarely have clear recourse if systems fail, data is misused, or devices cause harm.

Principles for a rights-based future

Yet technology itself is not inherently harmful. As our report argues, digital tools could be part of the solution, but only if they are reoriented away from enforcement and towards rights-based support. To that end, we set out ten Guiding Principles, including:

• No deprivation of liberty: Technology must not replicate detention in digital form, depriving people of their liberty.
• Free and informed consent: Participation must be voluntary, with clear rights to opt out.
• Oversight and review: Independent bodies must monitor impacts and provide pathways to challenge conditions.
• Public interest over profit: Outsourcing to private contractors must be strictly regulated, with transparency and accountability.
• Engagement, not enforcement: Digital tools should enhance case management and community support, not criminalize, coerce, or stigmatize.

If used at all, technology should work to reduce detention, not expand it.

A different vision of technology

There are already glimpses of what this different vision could look like. In some jurisdictions, digital case management platforms are being piloted to connect people on the move with lawyers and service providers, enabling faster resolution of cases. Community-designed apps provide people with information about healthcare, housing, and education. When technologies are grounded in rights and co-designed with affected communities, they foster trust rather than fear.

But these examples remain the exception. Without a shift in policy, the dominant trajectory will continue to be digital surveillance, an invisible leash replacing the bars of detention centers.

Breaking the leash

A story from a woman who crossed the US-Mexico border that informed the composite attributed to Mariela above is emblematic. She was told the ankle monitor and SmartLINK app were “alternatives” that gave her freedom. But the constant buzz of the bracelet, the random demands of the app, and the gnawing fear of deportation left her feeling no freer than inside la hielera.

The choice before us is clear. Will technology be harnessed to entrench surveillance and coercion, or to expand freedom and dignity? If governments, international organizations, and technologists commit to rights-based principles, technology could help dismantle the detention system and support community integration. If not, the invisible leash will become one of the defining features of immigration control in the 21st century.

The stakes are high. True, rights-based and community-centered alternatives to detention are possible. We should not mistake surveillance for freedom.