We should save this for post game, right now people's opinions are tainted by their roles, current scummers probably lean against but don't dare speak up against or might speak for to look pro-town, townies might favor it now or not want to say against since it might make them look scum. As is, I'm sure suspicion is heightened on me right now and I'm probably freest to speak against it, as our nominal Dark Lord Emeritus and the person who primarily keeps our rules and chronicles. So, I think we should shelve this till post game, when people are free to talk and have had time to consider it.

To your point though, we certainly have no business writing into the rules whether or not a Mod has to ignore commentary from a player via NB, and I really can't conceive of a phrasing that would do it. "All statements in the game are to be taken at their face value" only opens up the floodgate - Fox, the Scummers are supposed to lie, I do it rarely as one only because I worry about being caught out by my own bad memory, exterior proof, or a lie detector... and because I derive perverse amusement from it too. Nothing is stopping a lie detector from sifting through everyone's comments to find possible lies, let them work for it or they become more powerful than a cop, at least a cop is tempered by possible insanity. Our job as players is make everyone keep talking so its there... look, pick a few players and I'll hand you a small hoard of comments by them that render the 'NB to Mod' language twist meaningless, because no one is going to NB the Mod every time they post to clarify mistakes they probably didn't see on the off chance there is a lie detector and that specific comment is targeted. And I still see no way in which we could do this anyway, and let's not forget the actual role here:

Each night the Lie Detector sends the Moderator a post made by another player during the previous day [note, previous day, we'd have to do it every single day to be useful], and the Moderator tells the Lie Detector, to the best of his ability, whether that other player was telling the truth when they made that post. The power can be used, for example, to find out whether a role claim is true or not.

In one form of the role, the Lie Detector's ability is lost if he tells the other players, or they work out, what his ability is.

Bold mine, and that's the core point, if I tell the mod I was making a true statement, it's done. I don't see any wiggle room in that. "I was talking about the real mafia, not the game" ends the discussion, because the mod can't and shouldn't be trying to figure out if that's true, they know the player's intent was deception, and that's fine, the mod is explicitly not to there to worry about lying or deception in game, and if I write a comment and explain to the mod that I specifically meant it as X then and I wrote X then I'm manifestly telling the truth and the mod knows it.