@Bas: Well, probably my setup is a bit uncommon, as I have several devices with different keyboard layouts (and soon enough I'll get a Surface from the UK).
Leaving my work PC on overnight would mean a lot of fun at home with my laptop (I cannot RDP to my work PC - I know, don't ask). Of course this would hardly be an issue if I had the same keyboard everywhere, but then I wouldn't need synchronizing anyway.
Different issue with the language. What language I use depends on the task at hand, not my mood or the phase of the moon; if I happen to write an email in some language, it doesn't mean I want everything else set to that language everywhere.
Of course I can just stop synchronizing, which is what I did, but I am just curious to know what was the compelling scenario they had in mind when they designed this feature.
What you suggested about using a public PC in Korea probably would work, except I cannot remember when I used a public PC in this century, and I'm not sure I'll use one again, like, ever. Am I missing something here?