Actually her being mentioned as a "pretender" makes me think it could be a way to find out if her and Quicksilver are really Erick children and mutants. I always liked the concept of Magneto having twin children, but thought it went the wrong route before it could be fully fleshed out. It is several ways to streamline their origin.
I don't think she should stand trial now. I think they should really find out and delve into the house of Magnus.