I firmly believe that alt codes shouldn’t be allowed, period. At least for NA servers. All they do is create an annoyance when trying to whisper, /who, invite, mail, whatever someone based on being told the name.
If it’s not commonly on a standard keyboard, it shouldn’t be available for names, regardless of the handful of legitimate uses for them. It’s just a matter of usability. I should never have to google an alt code chart for WoW.