The teacher’s union would then protect the teacher by pointing out to the education district that their member had been investigated by the police and found innocent, regardless of their own rules. Usually, the education district would then just remind the teacher of their own guidelines, as before.
If things got too hot for the teacher, he’d just move to another school (carefully chosen) and start again. How do we know? Because we have the case histories of endless teachers that ended up going ‘too far’ (in reality, the very first complaint should have had the bastard sacked and barred).