... You know, reading some of the replies and attitudes here towards the nudes part, the phrase "It's her fault for dressing so provocatively" comes to mind.
Edit: Compassion 101, because apparently we're doing this:
You have no right to tell anyone what to do with their body provided that everyone consents and fully understands the situation.
If you know things that they might have missed, gently let them know, but back off if they don't want your input.
If something bad happens to someone, even if it is their fault, for the love of god don't lecture them on how it was their fault. Give them emotional support and advice on how to fix things, not what they should have done in the past.