I heard that the US-first DK (Essay on Tichondrius) is a boxer. He used the out-of-group tap technique with his 4? 5? box team to power level his DK through Outlands and into Northrend.

Re: Athene, he asked the first GM if out-of-group tapping was legal. It is. However out-of-group tapping in an instance is exploiting (as you're circumventing the "not part of this instances group" by repeatedly joining/leaving the group.) Neither GM was in the wrong, and neither contradicted each other, they were simply not in the same context even if it looks like they're talking about the same thing on his page.