A Danger Most Parents Don't See Coming

I am going to give you a scenario that most parents wouldn't see coming:

So, parents of a 7 year old has taught their daughter repeatedly about the dangers of strangers. They have talked with her over and over again about how no one is to ever touch her on her privates and how she is to scream and run away if anyone does.
 She understands and promises to do just this.
Well, one night a friend of hers asks to spend the night as she has done before. The girls are close in age but with the 7 year old being younger. Late that night the parents go to check on the girls and make sure they are asleep and to turn off the tv they fell asleep to.
However, what they found was the older girl perpetrating on their 7 year old. Now, what they did not know was that the other girl had been sexually abused by her former step-father and was now wanting to show that experience with other kids.
These parents had no idea that this had also occurred the time before when the girl had spent the night. They had always been so sure their daughter would tell and run away if she were ever put in this situation. But she didn't! And she can't explain why.

Here are the questions: Are our children assuming that it is only bad if it is an adult that tries to do this to them? Is the peer pressure so effective at this age that they won't tell on a friend? Do we now have to cut out a big part of being a child and ban sleepovers? Do we interrogate parents of the friends to find out if their kid have been a victim of sexual abuse? How do we protect our kids from victims that turn perpetrator without condemning the kid when it wasn't their fault they were abused?

Our child safety books also need to elaborate on the fact that the danger can also come from a child they know.

I don't have the answers to these questions, but this is a real danger we need to accept and protect against.

I look forward to your opinions on the matter!

Citizen Out