Maybe no lock down as in the UK but they do have a very intrusive "universal contact tracing strategy" which allows for selective lock downs / quarantines to be imposed.
Quoting Forbes
South Korea has effectively flattened its curve without imposing strict stay-home measures of other countries by developing an aggressive and widespread strategy of testing and contact tracing. With free, 10-minute tests conducted in drive-thru and walk-in centers, the country of 51 million had tested over 270,000 people by mid-March, reports the Guardian.
Further, utilizing GPS phone tracking, CCTV and credit card transaction monitoring, the country employs a comprehensive universal contact tracing strategy—automating alerts to people who may have been exposed to COVID-19 via text message. Officials say this system requires only 10-minutes per case.
These will be the same tests that have lead to the (now, considered by many virologists, incorrect) conclusion that previously-infected people can be reinfected.
Person tested.
- positive result
- patient recovers
- negative result*
- subsequent test gives positive result
Many virologists believe that this * result was erroneous; Cambridge's Dr Chris Smith has reported that the quick(ish) tests are c. 65% accurate i.e. barely better than flipping a coin.
All we can be sure of, of the above, is that the tests being reported in the above are little better than guesses.
As these tests are the basis for all of the other measures - contact tracing, text message warnings, imposed selective lockdown / quarantining, etc - is it acceptable to impose all of those measures on random people, based on little more than guessing?
Perhaps more pertinently, is any good done overall, by locking down uninfected people, yet not locking down those who have returned false-negative results (and this is without considering the
significant proportion of infected people who show no symptoms anyway)?
