Steph: So the problem really is the fact that the JW do not encourage the victims to seek out help from the police in order to get the second witness
Exactly.
A child who says "I have been abused/raped/touched, etc is the first witness. The second witness may very well be the medical report that the police would pursue if and when they were contacted. The second witness then becomes the physical evidence that the doctor finds. Like ripped anal tissue, vaginal tears, etc. Second witness is forensic evidence that is discovered if and when the child is taken to the police/doctor.
Eyewitnesses are unreliable. Physical evidence is reliable and valid.