One day, bored, I decided to go solo Vortex Pinnacle on my hunter.
Once I got to the 2 Howling Gales (The ones that knock you back), I tried to mess around with them.
Anyways, a few moments later I found out that you can trap them, and knock them around with a rhino (Exotic pet) knockback.
I got myself 5 rhinos, and after a while I had knocked the gale all the way to the spot where the people are teleported to when they use the Slipstream teleport.
Then I got a tank friend in my group, and we queued to get more people - they appeared at the start, and when they used the teleport they got instantly knocked away.
We laughed so hard at the people trying desperately to get past the NPC, until one of them broke the trap.. Anyways, this is a bit risky cause it might count as an offense since you're hindering the progress.
Fun nonetheless.
(some screens will be posted when I go there again)
EDIT: Video coming in a few days