It may happen on Viki as well. I see many Ko-En subbers not take into account the era/social status/age at all. I remember on a sageuk, there were servants saying "Okay" to their master or ministers to the king!
Even in modern dramas like Secretary Kim, I always edited "okay" from an employee to the CEO or vice-president to "all right" or "Yes sir", while I left it between colleagues/friends, so that there could be a noticeable difference in tone to show the hierarchy levels.
I feel that Koreans, who come from a culture of many different and very specific degrees of formality, when they come into contact with English, they think that because it doesn't have the sort of distinctions they have, there are no distinctions at all, and that's why they are not careful at all when translating. They make Western society more "democratic" than it really is.
But it's not true that there are no distinctions! Yes, there's no distinction between thou/you, as there was in the past, but there are other ways of showing respect.
"Hey you!" ---- "Excuse me, sir!"
"Okay, got it!" ---- "Yes, sir! Understood!/It will be done!"
"Are you kidding me? What is this B.S.?" ---- "I don't seem to understand what you're saying"
"Come, come, sit down!" ------ "Please have a seat, ma'am".
"Hello, boss!" ---- "Good morning Mr. President"
"Bye! See you!" --- "Goodbye, see you tomorrow". (even that, "see you" is not very formal.)
"How about we go grab some chicken and beer?" --- "Would you like to have dinner together?"