I dont know about u but most often happens to me to go to the WC during a BG, when i come back i dont even notice the inactive debuff and for example AV i run run run for north bunker and bam gets kicked. So what i suggest is to make an addon that will make a sound when u get Inactive buff or during being Inactive
You may want to consider using the Master channel instead. Sound Effects are extremely spammy, especially in combat, and I don't know anyone who plays with Sound Effects turned on at all. I turned them off back in the Burning Crusade; hearing Chain Heal nonstop for 2 years was more than enough.
Plus, if your sounds are on the Master channel, then their volume can be adjusted independently of the game's normal sound effects, so users can set your sound at a higher volume so it's easier to hear against the cacophony of combat sounds.