My experience goes a little something like this. A few days after I came back from Sydney, I was manouvering my overflowing trolley to the cashier at Costco and my phone rang. Not the best timing but I had been ignoring several calls from numbers I don't recognise and figured that this person was persistent... could be important.
Caller: Yoboseyo. <Followed by a string of Korean words that I did not understand>
Me: Hangukmal murumnida
Caller: I am calling from the CDC. (Me: CDC??? Center for Disease Control? Uh oh!) You have recently returned from Australia? (Me: Ooooh, nice sounding young man with good command of English)
Me: Yes.
Caller: Do you have any flu symptoms?
Me: No.
Caller: Are you sure?
Me: No cough or cold or runny nose.
Caller: Please monitor for the next week. If you have any flu symptoms please go to the nearest public health centre.
Me: Ok.
Caller: Goodbye.
Me: <Turns to M> **E! You are not going to believe who called me! CDC!!