As the other tank in the author's FC, I can verify that no ninja I have seen will EVER let the warrior slashing debuff remain up. I have come to believe that many on the Aether cluster view this icon as a direct challenge, and will take the first opportunity that presents itself to bring it low.

Offtopic: I've been enjoying both healers when tanking as a DRK, AST makes me a little nervous when I drop down to the 30-40% range. I know the Essential Dignity is coming, it's just scary for me to be down there.