i know this bug since tbc and its still working with 3.3.3.
it's very easy to use ->
When you kill a NPC, you'll automatically get ooc after 2secs (only works when you're fighting against an enemy player).
step1: kill a npc
step2: wait 2secs
step3: -> ooc
especially if your an engineer, you can use your "hand-mounted-pyro-rocket" after cc'ing an enemy. then you'll get ooc and can regg, mount up, restealth or whatever.
it's very helpful in openpvp and in duels aswell
enjoy! (sorry for my english)
edit: I attached an unlisted video, it should look like this:
//edit: still works with 4.0.1 EU Live & Cata Beta