And you would do this... How?
Is it so difficult to know what is going on in your own household?
I had kids who grew up in my house, and I was more than able to know what was going on.
It's called watching and being aware.
Justice is letting a rapist live?
Now it's rape?
You are talking two children in the same family, correct?
Or has the story changed that much?
I do NOT believe in enforcing the Law of Moses in my household, if we're back to that again.
Does justice depend on what the sister wants?
The victim should have a say.
In other words, is the standard of justice arbitrary?
I have no idea what you mean by that. It could be anything.
I would say discretion would be required ie "discretion of the judge".