I have known of 5 in congregations I attended. None were reported to the authorities. One was df'd but then reinstated 7 months later. One "confessed" after his child approached someone outside the family. He got a private reproof and "restrictions" which was useless since he had no "privileges." I know one that 5 years later told people that he had told the JC he was guilty but he wasn't.
In all cases no one outside the family or JC had a clue these were molesters and when they moved, no elders told the new elders.
The thing to remember is that pedophiles are everywhere known and unknown. Also the elders only report in states where it is required by law. Remember that the laws are different regarding "clergy" which is what the WTS considers elders when dealing with pedophiles....confidentiality clause.