They knew being straightened out / slapped around in public but do nothing about it
The Corleones were “pretending that they were "weak" and ready to be knocked over” and continued their strategy by doing nothing when Fredo was being straightened out / slapped around in public by Greene and It worked!
As Greene [and everyone] believed -
First of all, you're all done The Corleone Family don't even have that kind of muscle anymore The Godfather's sick, right?
You're getting chased out of New York by Barzini and the other Families
