There're plenty of articles written about how South Korea has helped contain its COVID-19 outbreak. Example.
One paragraph in particular catches my eye:
People ordered into self-quarantine must download another app, which alerts officials if a patient ventures out of isolation. Fines for violations can reach $2,500.
The same paragraph in another article:
That person is then put under monitored self-isolation for two weeks, using an app that tracks his phone to insure that he isn’t breaking quarantine.
How would this work for people without mobile phones? Does the state provide these people with a phone? I've not been able to find details anywhere.