Countries around the world are rushing to use technology to help slow the spread of the coronavirus. Some governments are tracking citizens with the help of apps, drones and other high-tech methods, but critics warn the surveillance may go too far.

In China, drones pick out perpetrators in public, ordering people to wear masks. In South Korea, special cameras expose anyone with a fever. And in Tunisia, a police robot questions suspected violators of the country's lockdown.

Milo Hsieh, a student at American University in Washington, D.C., said when he flew home to Taiwan last month, authorities told him to quarantine at home for two weeks.

"I had to fill out a form, putting in my address, my ID number and all that for them to track me," he told CBS News foreign correspondent Roxana Saberi. "They verbally told me that, you know, your phone will be satellite tracked."

But he didn't realize how closely it would be tracked.

"My phone ran out of battery for about 15 minutes," he said. "I plugged it in … but by then, there was already two police officers knocking on my door."

Hsieh said "it's a little scary" that officials have the capability to do that level of tracking and enforcement.

It's also a concern raised by privacy advocates like Estelle Masse.

"Governments do need data to fight the spread of the virus, but ... knowing at what time I go to the shop, if I'm not infected, knowing who I might be meeting there, is not relevant," Masse said.

The extent of surveillance varies from country to country. In Europe, voluntary apps track people's symptoms, and one in Israel even alerts users if they've come into contact with someone who's infected.

Now Google and Apple say they're building similar contact-tracing technology into smartphones, a move President Donald Trump said his administration is looking into. Already, U.S. officials are turning to tech companies to tap into digital data to see if people are practicing social distancing.

In London, data gathered by Google shows where the U.K.'s lockdown is working. Visits to shops are down 84% and visits to workplaces are down 61%, but visits to parks, where police have had to send sunbathers home, have dropped only 15%.

"That is very useful data, and it is very easy to keep that anonymous," said CBS News contributor and Wired editor-in-chief Nick Thompson. "The next step would be when the government starts to track individuals. We don't know when that will happen."

Asked how unprecedented this type of technology is, Thompson said, "I don't think we've ever had a moment where people are willing to say, 'OK, you can use my phone to identify every person I've been near, and I'm OK with that.' That is new, but everything about coronavirus is new."

The contact-tracing technology is not being widely used in the U.S. yet. And so far, it's been up to individuals to download an app and share their details.