Earlier this year, Chicago officers strapped an ankle monitor onto Shawn, a 15-year-old awaiting trial on charges of robbery. The ankle monitor offered police the ability to track Shawn’s whereabouts, helping ensure he’d show up for his court date. But unlike traditional ankle monitors, Shawn’s was equipped with speakers and a microphone, theoretically enabling two-way communication between Shawn and law enforcement. His mom told the Appeal that she worried that officials were eavesdropping on them: “[T]hey can hear everything. We could be here talking about anything.”

According to the Appeal, Cook County officials use these capabilities to remind children about upcoming court dates or to charge their monitoring devices, but “no probation officer has used the device in violation of the law.” But Shawn’s case may be just the beginning. Historically, electronic monitoring devices were designed to provide information on geolocation only (and warn officials if an individual attempted to tamper with the device). Lately, however, officials in D.C., Chicago, and elsewhere have started using devices that have two-way communication capabilities. Although these new devices promise some added benefits, those are overshadowed by significant costs to dignity, privacy, and rehabilitation.

On any given day, more than 100,000 people in the criminal justice system are under some form of electronic monitoring, a number that has increased by 140 percent in the past decade. Most commonly, this entails wearing a device around the ankle—the prototypical GPS ankle bracelet—while the individual is released on community supervision. Community supervision encompasses programs where individuals are monitored by law enforcement but are in their own community instead of behind bars; it can be used either pretrial or after adjudication, such as with probation and parole. The ankle bracelet may not technically be mandatory in many instances, but the individual usually has just two choices: monitoring or incarceration.

Just as people awaiting trial often prefer monitoring, so, increasingly, do jurisdictions. Many prisons and jails have reached capacity, and opposition to cash bail is growing. That makes community supervision an appealing alternative to both pretrial detention and post-conviction incarceration, but whether even standard electronic monitoring produces improved liberty or undue interference in an individual’s life often depends on one’s perspective. To many prosecutors and judges, it serves as one of the only alternatives to incarceration for individuals deemed higher risk. To many civil liberties and criminal justice advocates, it represents an unnecessary and burdensome form of “e-carceration” for individuals who would comply with court conditions even without such monitoring.

But in a system where some form of incarceration is the only alternative, a return to the community may well seem worth the inconvenience and surveillance that come with electronic monitoring. There’s also some evidence that electronic monitoring may reduce the likelihood of a person reoffending, though the research is not entirely clear. And the projected cost savings of monitoring over incarceration are attractive to government officials who feel that some sort of enhanced supervision is necessary for a given individual.

We must ensure that any developments adopted for criminal justice purposes are in fact in line with justice.

It seems almost natural that as technology advances, so would the specs of electronic monitoring devices. In 2014, the company SecureAlert, now known as Track Group, released the ReliAlert XC3, the two-way device Shawn and others have been required to wear. It boasts improved cellular range and clarity, a 60-hour battery life, and a new tamper-proof alarm, in addition to its speakers and microphone. Those calling capabilities could allow officers to get in touch with individuals on probation, who can be hard to reach, or let probation departments issue warnings that an individual is close to violating curfew or traveling outside of an allowed area. The advertising materials for the ReliAlert XC3 claim “real-time violation intervention.” One watchlike monitoring device from another company promises not only calling features but “motion sensors, vibration alerts, messaging, heart rate and blood pressure detection.” It does not as yet appear to be in use, but someday these enhancements could reduce sources of miscommunication and potentially prevent violations before they occur.

But that ostensible protection comes at the price of increasingly intense and granular surveillance, not to mention intrusion into individuals’ lives. When probation and police officers are able to call individuals through their devices, they can do so at any time without warning—and their calls cannot be refused. Officials say they are not using the enhanced features and have merely adopted these new monitors for other benefits like improved battery life. But there has been at least one report of an individual receiving a call anyway.

Even more troublingly, the two-way communication features of some of these devices mean that whoever is doing the supervising can listen in on them at any time, anywhere. This represents a massive, potentially ongoing invasion of privacy, even for probationers who have diminished rights to privacy under law. Perhaps of most legal consequence is the ability to listen in on conversations with one’s attorney, which undermines attorney-client confidentiality and violates the constitutional right to counsel.

By turning probationers into listening posts, the devices also risk violations of third-party privacy rights—as conversations with one’s family or employer, for example, become exposed to government surveillance. In some states, like Illinois and California, this is illegal: Wiretapping laws forbid listening in or recording a conversation without the consent of all parties. But even where it is wholly legal, this capability is likely to serve as a source of isolation for the person being monitored, since few of us would invite the government to surveil even our most innocent conversations.

The next step here might be physiological eavesdropping that could expose an individual’s health conditions, sleep patterns, or even insight into their moods. Add sophisticated algorithmic analysis, and this type of monitoring could border on the predictive. One wearable in the consumer space, for instance, is designed to predict when a couple might be about to have a fight.

Community supervision is not just about monitoring and surveillance; it’s about rehabilitation and helping individuals reenter society. Likewise, in designing community supervision programs and products, we cannot limit ourselves to the preferences or needs of the people in charge of those programs, or the people placing the purchase orders for those products. Pretrial services and probation departments are incentivized to prioritize public safety over all other goals—they are punished for enforcement failures but are not rewarded for successes, since those individuals do not come back to the system. It’s no surprise, then, that the technology is designed almost exclusively with monitoring and surveillance in mind.

Many of these monitoring devices have been attached to individuals who have not even been convicted of a crime—namely those under pretrial supervision while awaiting their day in court. These people retain the presumption of innocence, making the privacy invasion features of these devices that much more galling. Electronic supervision in the pretrial context is meant to ensure that these people return to court and to deter them from committing a crime in the interim. It is unclear that calling or listening features are necessary to advance that mission. Sometimes the simplest innovations can be the most effective: For example, the criminal justice system has already found great success in sending defendants text reminders of their court dates—a method that implicates few, if any, privacy concerns.

While makers of wearable technology will continue to iterate and innovate, we must ensure that any developments adopted for criminal justice purposes are in fact in line with justice. It is essential that new devices respect the privacy and dignity of the individual and don’t add new features unnecessarily. Shawn, for example, told the Appeal that the monitor makes him feel like a slave and doesn’t leave him room to think.

“Supervision” is only half of the community supervision equation. Monitoring has to allow individuals to move forward with their lives and once again be, simply, full members of the community.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.