I just finished reading the novel for the second time - I officialy decided that if (when) I read it again, I'll just skip the whole story on Lucy Mancini's background. that is BORING! - and just for the sake of the discussion, I was trying to find the most unrealistic event of the novel and I believe hands down it was Barzini's shooting.

I know he was meant to get caught off guard, but still, didn't the Corleones relied too much on luck with that plan? like I said in another thread (in the film boards) "Neri just shot Barzini 3 times in front of 2 bodyguards and a driver and escaped walking into the crowd".

maybe the Corleones had such excellet inside information, they found out that for some reason Barzini was so "safe" in that place, the bodyguards weren't even carrying their weapons, which I do not belive it is very likely.