I still dont beleive that pets can get agro. I have never witnessed that where it couldn't be explained.
Pulling(pets can grab the agro easy with a taunt from a moving PC)
Reposte(you can often see the NPC turn for a brief moment while he knocks the pet a new one)
Possitioning/root going off(tank getting hit with a minor knockback, taking a step back, etc. Also, rooting changes things up a little)
Anyways, i know it cant be argued, and only explained by a GM, admin, or Wiz, but i did test this with a chanter pet and couldn't get him to take agro away when i was in melee range(actually attacking) the mob.
Anyways, enough about that. /pet no taunt effectively drops taunt from your pets to-do list. If a pet isn't taunting, then the only agro it can get should be as follows:
Melee DMG
Spell DMG/Debuff(not really an SK pet issue)
Other DMG (bash, kick, riposte, all specials)
Also, low life agro seems to work on pets. Many a time i have seen nearby low level monsters that would not normally assist while my pet is fighting, swarm him when he gets under or around 20% health.
My suggestion would be to watch your next few fights with the pet. Stay in very close melee range and note when/why/how your pet gets agro away from you while you are within range to be hit by the NPC.