Originally Posted by
ComputerNerd
Before anyone questions it, yes that is a perfectly acceptable system to use.
You are simply adding an additional file to the wow folder, an alternative sound which the client will use rather than the default one.
It can be done using a similar method to mute selected sounds, particular examples being to silence spellcasting/attacks so that a boss fight being recorded / streamed has less unecessary audio, or for "annoying" sounds such as selected pets/mounts etc.
A similar method also exists for replacement of many UI elements such as buttons, frames etc.
Modifying the game client files is what blizzard prohibits, not this.