It's like this. The existence of the LCN is an established fact proven in past court cases. The initiation ceremony is part of what makes up the LCN. Mob guys actually being caught in the very act of the ceremony could go towards evidence of conspiracy in a given case. In other words, while they couldn't be prosecuted directly simply for having their fingers pricked, reciting some words, and burning a saint card, all of that could be folded as evidence into a larger RICO case.