If you stand atop of that pier that holds a horde banner, like this
http://www.vojkolon.com/wow10.jpg
than Alt+F4, and than you enter a game again, you will fall down, as shown on this pic
http://www.vojkolon.com/wow12.jpg
http://www.vojkolon.com/wow11.jpg
No one could see you unless you have some long title I suppose.
if you use "Log out", it's just not working. No idea what this could be usefull for, except some trolling. You are vulnerable. Tried with a rogue and human lock.
Edit: Get in that box under it :
A friend showed me this. We tried on ally's terace. Thers no pier there, only that square. Stand on the edge of that square (the edge facing your town's building), as close as you can to the edge, without falling down. Mount yourself, use one of big mounts. Duel a friend. He need to cast Blinding light, or Blind, or some disorienting spell, depends on class ofc. You'l start to walk mindlesly around, fall down, continue walking, and eventually enter through texture, into that box. Need a few tries.