In Vienna, Kat meets up with Uncle Eddie, who tells her that Visily Romani is not a real person. "He is not one. […] He is everyone" (12.28).
The name "Visily Romani" is a Chelovek Pseudonima, which is a wacky name for an alias passed down through the big thieving families, across multiple generations.
So, knowing the name "Visily Romani" doesn't narrow anything down for our thieving team. To make matters worse, Uncle Eddie demands that "Any job done in the name of Visily Romani will not be undone by children!" (12.44)
And that's the end of Heist Society.
Just kidding. Do you really think Kat would let one little warning from Uncle Eddie stop her in her tracks?