I think you're absolutely right. Not sure about Korean, but Japanese youngn's have already invented their own obfuscated script called ギャル文字 (Gyaru-moji):
http://en.wikipedia.org/wiki/Gyaru-moji. I've tried to read it but it's quite difficult. What's interesting, however, is how fast it could evolve. The authorities will have a hard time keeping up even when they do catch on.