The Hong Kong government has issued 30 families recently returned from Hubei province—the epicenter of the ongoing coronavirus epidemic—with location trackers, walking a fine line between quarantine and house arrest as the suspected patients are confined to their homes for 14 days.
“These are people who have to be quarantined at home, they are not criminals, so we agree we have to respect their privacy,” the Hong Kong government’s chief information officer Victor Lam said during a press conference on Monday, where he modeled the wristbands that the quarantined people will have to wear at all times.
The chunky wristbands connect wirelessly to a battery-less smartphone, provided by the government, that has to be plugged in at all times. If the wristband moves more than 30 meters from the phone, or if either device breaks, the Department of Health will be notified.
Because the tracking devices don’t have GPS and can’t monitor a wearer’s exact location should they leave the house, Lam said the wristbands are mindful of privacy. People who violate quarantine, however, are considered criminals and are liable for a prison sentence of up to six months and a fine of $640.
Trailed by tech
Hong Kong has 500 trackers ready to slap on the wrists of the quarantined and, according to Lam, it can acquire another 1,000 in two weeks if necessary. The use of electronic trackers in the case of quarantine seems novel but has happened before.
Singapore used trackers and webcams to monitor home quarantine patients during the SARS pandemic of 2003, which infected 238 people and killed 33 in the city of 4 million. Reportedly, the city state ultimately placed close to 8,000 people under quarantine during the SARS epidemic under threat of a roughly $7,000 fine and six months jail time should they violate the lockdown.
Today, amid the Wuhan virus, other regions are deploying tech to monitor suspected victims, too. In Taiwan, health officials have issued patients under house quarantine with location-tracking smartphones, which notify the user and police if they have ventured too far from home. The head of Taiwan’s Center for Disease Control said violating quarantine is punishable by a fine up to $9,000.
In mainland China, the center of the epidemic, the state’s various surveillance systems—including big data analysis—are being put to work to track thousands of suspected carriers of the virus. Officials in Chongqing claim to have used unspecified data to track over 5,000 individuals traveling from Hubei during Chinese New Year. Half of them were quarantined.
Private enterprises are contributing too. Baidu says its remote thermal monitoring system—which reportedly uses A.I. to direct an infrared sensor at the foreheads of moving passengers—has been deployed in railway stations and airports.
Online security firm Qihoo 360 has launched a program that allows users to check whether they recently travelled on the same train or plane as someone who was later diagnosed with the coronavirus.
Not all of the data used to track suspected patients remains in the hands of government officials. The Associated Press reports that residents in a Shanghai neighborhood are circulating a list containing the personal data of close to 200 people who in live in the area who have allegedly travelled to Wuhan. Similar reports of doxing are reverberating around China with victims reporting cases of being harassed by strangers.
“Quarantined people can feel like criminals, so I think pre-quarantine counseling is very important to make sure people understand the rationale behind the action, because basically you’re depriving them of their freedom of movement,” says Wong Tzewai, adjunct professor in the school of public health and primary care at the Chinese University of Hong Kong.
In Hong Kong, the Department of Health has published a list of the 24 housing estates where the quarantined residents live, as well as dates for when each unit’s quarantine is up.
At the press conference Monday, Director of Health Dr. Constance Chan urged residents living in the same block as the detainees to not panic—but Hong Kong citizens, like most others, are fearful of quarantine zones and distrustful of the government. In January, an empty public housing building was fire bombed after the block, which is in the heart of a residential zone, was designated a quarantine zone.
More must-read stories from Fortune:
—Coronavirus forces China’s neighbors to make tough choices
—Asia worries about big events like the Olympics amid coronavirus spread
—China will struggle to spend its way out of the coronavirus economic slowdown
—On facial recognition, Berlin and London choose different paths
—Fortune Explains: Tariffs and trade wars
Catch up with Data Sheet, Fortune’s daily digest on the business of tech.