First of all:
Didn't find anything so shouldn't be repost
Second:
This isn't totally an exploit, just a smart usage of game mechanics but still...
The deal is to cast something when you know a CC is inc (fear,blind,sheep etc) and spam your PvP trinket button. Duo to casting, you're unable to use trinket, but as soon as cast interupts duo CC, its instantly removed becouse you previusly spammed PvP trinket. Casters can cast any spells, hunters can go volley, rogues can buy a gray dagger and make a macro to put poison on it so they don't get confirimation of replacing old for sake of cast bar showing.Even heartstone works, any kind of cast bar spell/ability.
Heres an example to make it even more clear:
You are a rogue duelling another one. You got the opener, and as in 95% of times that rogue will trinket your kidneyshot.
What you do is wait a sec after you use kidney, then use your macro and start mashing that pvp trinket button. After he trinketed and blinded you, you removed it instantly and smashed his face with your blind. You win.
I hope I made this somehow clear, if needed I'll upload a movie.