As player Icki reported recently over at the World of Warcraft forums, there seems to be a serious bug with the Rogue class' shadowstep skill in the Test realms. The bug apparently enables rogues to literally shadowstep their way through different zones.

The matter appears to be serious enough that Icki's initial post illustrating the specific macro used was removed by blue-texter Hortus, who labelled the bug as a game exploit. Hortus further explained that they're currently looking into this matter.