I've known of male teachers who were serious predators, and rather than soil the image of a school have simply been moved to other towns. The same is true of priests who were moved to different dioceses to avoid scandal.
If a teacher comes forward and admits guilt it's the same as any other offence, the guilty plea was taken into consideration and it was decided on balance a custodial sentence wasn't warranted in this situation.
It should also be pointed out that there is no way this woman will be able to teach again, so she needs to find a new career.
Contrast this story with the appallingly short sentences given to these chaps click here. Quite rightly these sentences are now being reviewed...
As has been pointed out, if the teacher had been a male, and the pupil female, then we would have heard accusations of 'predatory', 'paedophilia' and the general societal (and possibly forum) condemnation.