Theres always a fine line between exploit and clever use of skills/mechanics :P Odd that they wouldnt reply though, but atleast it sort of proves it isnt a exploit and simply a clever little trick to make things easier.
Clever use of game mechanics is usually an exploit. :P That's just the spin players put on it to justify themselves.
I have been in a few 8-man groups with 4 ranged DPS where I NEVER MOVED from 28-29m from Zorn when the jump occurred. I have NEVER received the fearful debuff. Perhaps 8 and 16 man have different ranges?
I have never tried 16 man btw
I'm also in an 8 man only guild but I've always changed targets during the leap for 2 gcds (affliction/creeping terror onto torn) .