[summerlight]

Preserving privacy may inherently contradict with public interest coming from aggressive contact tracing. This is really unfortunate, but the S.Korea case could be even worse if adequate CDC agents were not granted with the authority to aggregate/join arbitrary private data (very likely against the subject's will).

This was especially important for early actions taken by S.Korea's CDC since a single super-spreader (#31) had contacts with thousands(!) of people within just 2~3 days. I'm 99% sure that Europe and America also have similar cases, but just remains unveiled because they couldn't really do the same thing with the given authority. S.Korea was in a similar situation during the MERS outbreak but now they passed a law to allow such actions.

IMHO, this trade-off is no brainer. The cost is can be controlled/minimized while the economical/societal damages caused by full lockdown is not. And yes, this is also not 2019 style free society.