Ankle monitors are trending these days: Movie mogul Harvey Weinstein and former Donald Trump campaign chair Paul Manafort are under the electronic tether, and last month, in the wake of outrage over immigration officials separating families at the border, US Immigration and Customs Enforcement began monitoring migrant parents electronically rather than keeping them incarcerated in detention centers. More than 35,000 immigrants have been assigned an ankle monitor GPS unit.

WIRED OPINION ABOUT James Kilgore (@waazn1), the author of the book Understanding Mass Incarceration and a 2017 Soros Justice Fellow, leads the Challenging E-Carceration Project. Emmett Sanders (@EmmettSanders75), a researcher on the Challenging E-Carceration project, is co-author of the guide "Mapping Your Future: A Guide to Successful Re-entry." They have both been on electronic monitors.

They have plenty of company. According to research by the Pew Charitable Trusts, law enforcement’s use of electronic monitors more than doubled between 2005 and 2015. The technology continues to gain popularity as pressure to reduce incarceration mounts. To many, electronic monitoring is humane—one that allows people “on the bracelet” to live at home and move about more freely than they would behind bars.

But those who have lived under this high-tech tether—including the two of us—see it differently. For many, electronic monitoring equals incarceration by another name. It is a shackle, rather than a bracelet. The rules for wearing a monitor are far more restrictive than most people realize. Most devices today have GPS tracking, recording every movement and potentially eroding rights in ways you can’t imagine.

Just ask James Morgan of Madison, Wisconsin, who spent several days behind bars because the Department of Corrections reported his monitor lost its GPS signal and reported false information about his location. Or Dustin Tirado of Los Angeles, who told us about cutting his hand in a domestic accident. The wound was bleeding profusely, so he headed for the hospital, phoning his parole officer to let him know. When Tirado arrived at the hospital, police were waiting. They took him into custody, and he spent 10 days in prison before being released.

We have been researching electronic monitoring for several years. There is no real proof that these devices make communities safer. Instead, the monitors function as an additional punishment, extending a person’s sentence when they’re placed on a monitor as part of parole. Or, they severely curtail the freedoms of those who are given a device before they've even been convicted. The money spent on this under-regulated and misunderstood technology would be better used to provide jobs or housing.

Here are seven things you may not know about the ankle shackle:

1. Paying for the Privilege

People on the monitor not only must live with round-the-clock surveillance; most also must pay for the privilege. Fees range from $5 to $25 a day, in some cases making a person’s monitor fees more than their monthly rent. Missing a payment has serious consequences. In Kentucky, if you are three days late, authorities can send you back to prison.

2. Can’t Touch This

Some people report skin irritations from the devices. Yet many states have made it a crime to “tamper” with or remove them; in Georgia, doing so can earn you up to five years in prison.

3. Shackled for Life

A number of states have mandatory lifetime GPS for people found guilty of certain sex crimes. In Michigan, those on lifetime GPS must shoulder fees regardless of their ability to pay. The Eighth Amendment states, “Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.” Doesn't a daily fee for the rest of a person’s life fall into the excessive category?

4. Don’t Get Sick

Some medical procedures, such as MRIs, mammograms, x-Rays, and CT scans, cannot be done while a person has a monitor. Most states have no clear policy for removing the device in case of emergency. California’s rules require the person to “carry an activated … device to the medical procedure” (e.g., into the operating room).

5. Hidden Costs

Many states still require a landline telephone (yes, a landline) for their monitors, adding a cost many households have long since struck from the budget. In Iowa, if you lose or damage the tracking component of the device, you'll pay $795 to replace it; a missing power cord sets you back $55.

6. Can You Hear Me Now?

A person’s monitor must maintain contact with authorities to avoid violating the rules. However, losing signal is a common occurrence for most people on EM. The easiest way to lose connection is a dead battery. Most devices have batteries which need daily charging. While batteries are supposed to hold a charge for the entire day, they often fail, forcing individuals to either return home or plug them into a wall outlet in a public place. The most difficult moments come during power outages; Troy Hawkins, who spent time on a monitor in Wisconsin, reported that he was taken to jail for five days when a power outage caused his device to lose connection.