I think they did know it was Pop's birthday. I think they were in league with Barzini. They figured that Vito would be so enraged that he would move his operations out west so that he could retaliate against the Japanese Empire. That would leave Barzini free to operate in the east with the cooperation of the Nazis.
"Generosity. That was my first mistake." "Experience must be our only guide; reason may mislead us." "Instagram is Twitter for people who can't read."
