What you describe is the concept of the
Uncanny Valley.
The uncanny valley is a hypothesis in the field of human aesthetics which holds that when human features look and move almost, but not exactly, like natural human beings, it causes a response of revulsion among some human observers. Examples can be found in the fields of robotics,[1] 3D computer animation,[2][3] and in medical fields such as burn reconstruction, infectious diseases, neurological conditions, and plastic surgery.[4] The "valley" refers to the dip in a graph of the comfort level of humans as subjects move toward a healthy, natural human likeness described in a function of a subject's aesthetic acceptability.
The term was coined by the robotics professor Masahiro Mori as Bukimi no Tani Genshō (不気味の谷現象) in 1970. The hypothesis has been linked to Ernst Jentsch's concept of the "uncanny" identified in a 1906 essay, "On the Psychology of the Uncanny".[5][6][7] Jentsch's conception was elaborated by Sigmund Freud in a 1919 essay entitled "The Uncanny" ("Das Unheimliche").[8]
Turns out, people don't like robots that become too human, because they're close, but
not close enough. We react the same way to physical and mental deficits, subconsciously. That's what happens when scum try to come off as Town, instead of just playing the game as they would if they were Town. They seem off because they are off.
Remember where I said earlier that lies are easy to tell, but hard to tell convincingly?
Well, they're not hard to tell convincingly when they're not lies. So, as scum, either get the Town lying to itself, or, simply,
be Town, and then you're not lying.
With that argument, you could make the claim that a scum-tell is in fact a town-tell due to the fact that real scum would never slip up like that. In that case, we shouldn't be hunting for people who slip up, we should hunt for people who don't, under the concept that they wouldn't allow themselves that slip. What's your opinion of this analysis?
I think you're over-thinking it.
Here's the thing: Town doing real scum-hunting often look like scum because they're not nice about it. They jump to conclusions, they point fingers at random or with no fact-basiss to back it up, they say stupid stuff, they contradict themselves.
In short: they're human.
What SBC described was perfectly the Uncanny Valley. He described scum being so careful to tend their words and deeds that they did none of those things above, because they know they're scum, and they don't want to look scummy.
But real players don't play that way, unless their new or naive or just bad at playing. Some players have very obvious scum-tells as part of their meta (see,
Nerjin, it does play some value, even if it's a terrible thing to assume your fellow combatants are stupid).
Most players aren't that obvious. What looks like a good scum-tell, or a scum-slip, might just very well be them actively engaging in scum-hunting, or it might be a genuine tell, but without a Cop investigation, you'll never know, will you?
So, stop thinking so hard. Just pick a glass and drink the damn wine, because both glasses are poisoned, and the other guy's immune.