By Elysianfield (2,016 – 1·6·20) on 2010/05/26 (Patch 3.3.3)
Though there isn't really point in doing this as if your group fails at killing valks you'll probably wipe anyway, immediately after getting dropped off the ledge mages can blink back on to it (assuming they remember to point the right direction).
I'd assume that other classes would be able to do something similar as well, such as warlocks with their demonic circle.
upvote
Melilithia on 2012/08/22 (Patch 4.3.4)
Demonic Circle no longer works after Cataclysm, sadly... I found this out the hard way.