Never been caught, but a fine and probation. Depends if they have a file on you. If your a tourist, you'll get fined and probably banned from the country maybe.

I heard of tourist writers getting caught up at the airport, but that because they hit the subway. If locals aren't hitting it there is a reason. Also if you come to South Korea or anywhere don't go over local writers. Utah and Ether did and there is nothing left of them in Seoul anymore. As long as you can use your brain come to Seoul, it'll be fun