The Visual Studio .NET IDE just completely freaked out and went all Japanese on me. If you ever want to be scared witless, don't close the IDE for weeks on end and this too will happen to you. I've had Intellisense freak out before (giving me the hint I need to save my work shortly before the IDE decides to crash), but the IDE itself never freaked out before to change the actual text in the document to Japanese/Chinese characters. Source code really doesn't look very good in anything other than English 7-bit ASCII. I mean, UTF-16 might be okay from a visual perspective, but I doubt most compilers would enjoy dealing with that.
How does this relate to developing software? Well, don't do this. Users get confused easily. This sort of thing would only complicate their lives more and probably frustrate them to no end. Especially if they don't understand Japanese/Chinese/corrupt lines of text.