Okay, so here is a little back story on how I found this out... Before the new patch (3.2), I used to help my wife with killing her Champions at the Argent Tourney Grounds. She sucked at it, so I tossed on my tank gear, taunted it, and let her beat it down. It worked great, and was a nice work around for killing Champions faster.
So, when 3.2 was patched, and me and my wife logged in to do the dailies, we found out something terribad. When I taunted her Champion off her, within 3-5 seconds, it would go green and do the "It seems you need more practice blahblahblah" dealy like you lost. So basically it seems that Blizzard tried to "fix" people helping other people at the Champions right? WRONG! Any class that can taunt, can also do it to other people, and make their mobs despawn! I tested it on horde on my server, and they were getting PISSED, lol!
TLDR:
1. Get a toon that can taunt
2. Go to Champions Ring
3. Find someone else fighting their Champion
4. Taunt the Champion
5. Roll around laughing when their champion claims a win and despawns
Have fun pissing off your friends or the other faction!
(Also: I will post screen shots when servers are back up as well!)
EDIT:
Here is a screen shot of me taunting a Gnome Champion off a Horde who just challenged him. He seemed pretty confused.