This is tough, but I'm with Walkingfeather, though. Our kids have to learn sometime that being a Christian means reaching out to others. We choose to homeschool for this very reason. I want my kids to learn to reach out to other kids in a controlled atmosphere where we can talk and pray about what is going on.
If the school administration allowed a couple of struggling kids into the community to be witnessed to and ministered to, what is the harm?
My daughters school did this and it was a mistake. They couldn't get the girls to dress according to the code, they wore no bras and extremely short skirts. One went around threatening to beat anyones a$$ that got in her way. A boy they allowed in was caught selling drugs......it was disruptive in the extreme.
There is no harm, but nobody in this media is going to tell you if the girl was witnessed to, and being it's a Christian school I am sure she was. If she advocates on behalf of the two women she lives with, tries to "open the eyes" of others, which I strongly suspect is the case, how can a Christian school permit that???