I'll always use it in labyrinth of the ancients (Ancient Flare barrier wipes anyone?) and in PvP for callouts when I know people aren't paying attention. I'd rather piss off one player than have a wipe/ect

Preventing misuse is the fact that people would get offences on their accounts. If they're an idiot spamming them then just report them and SE will take care of it.

Wanting a mute for it counteracts what it can help, sooooooo