Thanks thenuclearwalrus.
@Wrathran : With some NPCs, like cenarion circle NPCs, you can hit them, keep aggro and kite them in order to stuck the NPC elsewhere.
I have seen this in moonglade with the NPC Lorelae Wintersong (hardly camped by horde and alli for her recipes).
She was stuck by an alli under the bridge, under water, after he has log off.