This is interesting in that I have a present application: someone else's terrible, awful, no good, very bad document I have to destroy, and frankly their status deserves a penalty. Quite a lot of this will involve the phrase "knew or should have known" in my response.

Saying this without seeming to expect telepathy or clairvoyance will be important to watch for, e.g. noting in every case the "should have known" vector and describing bad consequences of actions without ascribing a personal incompetence or malice to them. (I suspect incompetence combined with self-righteousness rather than malice per se. Would demonstrating the self-righteousness count as ad hominem?)

The tricky bit is the fine balance between "you catch more flies with honey than vinegar" and "kill it with fire for your own self-defence." I'm inclined to the latter by sheer annoyance, which means watch myself.