On the other hand. I've seen an issue when a couple is getting divorced and the wife accuses the husband of molesting a daughter. The daughter has no memory of it. Is it repressed? Is the divorce because of abuse? Or is the abuse accusation because of the divorce. The man is immediately not qualified for congregation priviledges. Given, maybe he's not being a good family head, what if he's innocent of molestation?
That should be for the courts and qualified psychologists, psychiatrists, child therapists, et al. to decide. Untrained, ignorant elders should never get involved in any way whatsoever trying to determine guilt or innocence of a criminal matter. Let the secular authorities handle such things, whilst the elder body tends to the spiritual needs of the congregation in the intervening time.
If he's innocent, then deal with it from a scriptural standpoint as you see fit using Jesus command of love as your guide.
What if a 19 year old gets in trouble with his 17 year old girlfriend? Should the congregation view him forever as a molester?
Criminally speaking it depends on the state. In Texas that relationship would not be illegal. The age of consent is 17 and/or a 3 year difference between partners. Morally I guess that's up to guys.