I don't think that simply telling Tony what happened and who did it (without actually asking him to do anything illegal in response) would have been illegal. Yes, common sense dictates that if you tell a Mafioso who likes you that you were raped and identify who the rapist was, it's extremely foreseeable that violent action will be taken. If Tony told her he was going to do something and she didn't go to the police with this information, I'm pretty sure she could be charged as an accessory or conspirator. But otherwise, I don't think she would technically have done anything that broke the law. It wouldn't be enough for a prosecutor to say it was common knowledge that Tony was a Mafia leader and she knew this when she told him. Remember that during the entire series, law enforcement was never able to prove in court that Tony actually was a criminal at all! Knowing something from a common sense standpoint doesn't necessarily mean it can be proven legally.