They should be prosecuted on a criminal charge, such as contributing to the delinquency of minors. I don't like any of the answers. See my response in the Forum. One teacher cannot make up for all the education which was not attained in previous years, and in my opinion, should not be held accountable in such cases. Parents are the first line of defense.
Criminals get away with too much.
Now that you mention it, I can see where the testimony is too easily tainted. Any prosecutor who does that should be thrown in jail. I don't like any of the choices. You'll see my response in the Forum. There is no easy solution to this web of intricate problems.