Just to add another voice to the views above, I would really like to have the option to watch words without being alerted to their use in personal messages. I understand that admins can, if we want, read users’ personal messages, but I would want that only to happen if we made an affirmative choice to read those messages, not for it to happen by accident because a PM showed up in our notifications whenever someone used a watched word.
On my instance, we recently made a policy change about how members can discuss a particular political issue. It’s an extremely touchy subject, one that our users hold conflicting views about, and one that can easily spiral out of control, so the watched words are to give the moderation team early warning that a discussion is taking place.
We do not want warning that individual users are discussing this topic in messages. I’m not going to name the political issue, but I imagine people reading this might be able to make a good guess. We don’t want to discourage discussion of this topic in personal messages, as I’m sure will happen if users become aware the moderators are reading their messages as a matter of course. We just want to use moderation tools to keep a handle on public discussions.