>>19671740Pretty much pattern recognition.
In the past, I've had the displeasure of having had to interact with quite a few really unpleasant, but otherwise posing as 'good and respectable' to many around them, people.
And so I've naturally grown to be able to recognize such people before even having to really deal with them myself, just by seeing them do their stuff from afar.
I wouldn't be able to pinpoint a single "Her action right here is part of the reason why..." type of thing - it's more like a subconcious feeling I get when I see people which simply fit the bill SOMEHOW.
It's basically a spidey-sense which I seem to have for unsavory types.
And Suisei just so happens to constantly activate that sensor for me.