[Magic.]

I don't think the school were right to encourage her to move out. they should have helped her talk to her parents and agree restrictions like not in their house etc.
My 17 year old sister moved in with her 21 year old boyfriend last year (they've been together since she was 14). My parents were never entirely happy with the relationship because of the age gap, but they just said like "keep your door open / no sex in our house", because they liked him but were still concerned. She fought with our parents about curfews, wanting to be out later than me even though I'm 3 years older. She saw a school counselor who encouraged her to stand up for her rights etc, which led to her moving out. Frankly it's destroyed our family and my two younger siblings are heartbroken by what she's done.
I think that sometimes you need to respect parents wishes. She could have had sex with him in other places, but told them she would respect the rules of their house. At least then she would have her parents to support her if the relationship breaks down. Kids shouldn't be encouraged to move out unless they're being abused, not just "they won't let me have sex" ...