I know Seoul is a big city with a big population but there is never anyone on the streets in the outside scenes. When shows are filmed in NYC or LA, you always see crowds on the streets when the characters are walking. Yuri & Taepung bump into each other on the street like they are the only people in the town. Even the scenes in the cafes are spooky because there is no one there.
I do not mean any insult/offence towards you by saying the following but,I believe,from your post that you have not travelled to many Asian cities.If you had,you'd know that much of the general public in many Asian cities would not act normal around film camera crews.That is,there will,inevitably,be those who'd readily do those laughable V-for-victory or "peace" signs with their fingers.Or,alternatively,they might do all sorts of funny things to get their few moments of fame.Over and above these guys,there will probably be many passerbys who'll slow down and stare at all the set-ups during the filming.This would obviously spoil the shots.Lastly,it must also be cheaper to shut off the streets from the general public,wherever the filming is taking place,rather than pay for "extras" to fill up the background scenes.
Compare this with the larger budgets(for "extras") that American shows usually have.
There are many scenes in which "extras" appear. The office bldg for instance has people coming in and out of the doors and walking in the lobby - there are people on the streets and there is ALWAYS traffic, as I was assured by my Korean Friends is the reality in Seoul.
Pilseung, you are so right about people - but don't just mention Asian cities, look at the idiotic behavior of some people when they see a TV news report being filmed, they stand in the back and make silly faces and gestures. and of course, the required V sign etc.
When there are movies shooting in Chicago, the police block the street and sometimes even the sidewalks - - so if you would look at a scene shot in Chicago, you might ask the same question, LOL . . that's show biz for 'ya . . ;D ;D
My former husband was one of those who could smell a tv camera anywhere in the area. I don't know how many times my kids would say, "Look, Mommy, Daddy's on tv again." And sure enough, there he was somewhere behind the reporter. Soapy, you used the words that I used to say, "idiotic behavior".
To say that it was embarrassing would be an understatement.