Why can't you use foreign characters in game names?

On Deathwing I tried creating a character with a name using a special "foreign" character (examples: é â ü etc)... but the game says only English characters are allowed. Why is this? Some languages actually use these characters...

Also, you guys have localized "foreign" sub-forums, so I don't know why you would exclude these from in-game character names. Can anyone shed light on this?

Enabling non-English characters would cause us more trouble than benefits (additional security layers, compatibility, part of the community being against the change etc.).