I think we should look at it for what it is, guys who have been scheming and scamming all their lives see yet another angle they can exploit and go for it. Sure, a very tiny few might believe in omerta or some street codes, and no matter how bad they are or how many rules they break, they can't bring themselves to break that one. If it was up to me, there wouldn't be any such thing as cooperation deals. You get caught, you face your own consequences.
The deals are important because one man in the right place can help to know and destroy the oc gruop,the worst thing is when give fill immunity a killer like Gravano that for 19 murders made few yeats and the feds gave him a golden watch as a gift.
