it has to be an actual lockup with his freedom of movement restricted to a small area (a building/compound). Just having to stay in country or in a city doesn't count.
Can NO right away if he gets out of South Korea legally and clearly.
Can NO if the current whole set of charges or threats of charge from his past actions through market creation time are settled (3/6/2025) without it happening.
Ways it can happen:
he's found guilty as normal and is sent to jail for 10 years.
before the result of the trial, he's taken into confinement AND he is found guilty and the pre-trial detention counts as time served in some way.
current trial ends without any jail/prison time, BUT the state then opens up new charges against him for past actions (from before this market creation)
On sequentiality: The time period must be continuous, 30 days.
More notes: Days out on supervised release do break up the 30 days. I'm not sure South Korea even has this, though.
Note: if he is confined pretrial for say 60 days, but is NOT found guilty, then that does NOT result in YES. This is about him being held in custody in a way such that afterwards it would be reasonable to say that he served some kind of confinement punishment legitimately from the point of view of South Korea. e.g. imagine he were taken into custody for "his protection" or because he runs out of money/food, but then found not guilty but still deported immediately after trial. It would not make much sense to say he "served time'. (This would NO). Yet in that situation, if he were found guilty and given a "time-served" sentence of 60 days, it would be reasonable to say he had served time. (This would YES).
So both don't want to have to say someone "served time" when they were found not guilty, and I also don't want to say someone didn't serve time when they in fact were confined & later found guilty.
Also: if at any instant this becomes true (pre-trail+guilty time served) or normal jail, if later on he appeals or whatever happens, then the YES would still stand. (but, if he isn't held pretrial, found guilty, serves 25 days then gets deported or escapes, that would not result in YES).
On ending
Note: If end date (june 30 2027) is reached without it happening yet, it will NO even if he's in the middle of a trial or even if it's in jail at that point (but hasn't reached 30 days yet)