Synx Gambit
From SA Mafia Wiki
The Synx gambit is some awful thing that Synx invented which never works. Basically the idea is that scum will act awkwardly when asked to make a post stating "I am scum". While most scum will post this sentence, it is their reaction afterwards which is telling of alignment. Or rather, not telling of alignment. Because it's a stupid thing that never works.
For obvious reasons this gambit is pretty easily foiled, so no one really uses it seriously. Also, like many things called a "gambit", it is not actually a gambit.
(I'm just saying.)