Ah Ok, that makes sense 
I’ve mainly seen the more senior police for example, doing it. You are right, I don’t think I have ever seen a young person doing it.
I have been watching as many Kdramas as possible so have been watching older shows as well, which is probably where I have heard it more. Obviously it never gets translated so it leaves you guessing
As soon as I sort some finances out I intend to start learning Korean. My dream is to one day watch the shows without subtitles at all 
Thank you!!