That is a good point, however to say that as a general rule they know they're going to be killed shouldn't be what we're trying to say. Wiseguys are blindsided all the time even at times they think they're doing nothing wrong. I think the books that Pistone put out were just discussing a healthy paranoia one should have when dealing with the mafia. Since he, as an undercover agent, had even more to fear than the average wiseguy.