Moral dilemma- snare someone quadding?

[Faerie Blossom]

I don't think I *get* the "it's okay to attack people if they're engaged with NPCs" thing, even after all this time. It's acceptable to do and I understand this, but is it okay to do it if it means certain death for the person? Up until now, I've only used it on bards when I had no other recourse, but now I'm wondering if I should use it more often. I'd only do it to people whom I know would do the same or similar to me (people I've had bad experiences with in the past), as I wouldn't want normal PKs to do it to me in retaliation.

When do you think it's okay to use snare/root?