Interestingly, while the book of Proverbs makes many comments about the parents' obligation to bring up their children the right way, it contains four times as much counsel for young ones to listen to and obey their parents.
Since when have they started weighting their doctrines by the number of times it is mentioned in scripture? In that case, there are arguably two scriptures by which the justify shunning. There is only one scripture about the two witness rule. By that rule, the showing of love and forgiveness among family members would take precedence, and the exposing of child molesters on the say so of the child would have been a matter of course.
Tammy