Dear coworker,

You have, from time to time, asked me to let you know about any mistakes in your writing. Thus, while you did not, in fact, ask me to proofread your log notes, I feel compelled to inform you that "[Client's sister #1], [client's sister #2], and [boss] had a three-way" is not an appropriate way to document a conference call.

Cheers,
firefly

P.S. The look on your face when I brought this to your attention--and explained--was priceless. I wish I'd had a camera.