Elder dubs have, in the past, used the 2 witness scripture to automatically prove an accuser wrong. They also use it to shirk off any responsibility to do something about the accused by passing off all jurisdiction onto the bible. "the bible says you need 2 witnesses, therefore you must be wrong"
Sorry, but the setting of your 2 witness "rule" is far fetched at the most. Its helped you out of a sticky situation in the past, so therefore it automatically must be good in any situation including horrific crimes such as child rape? mmm...