What they actually have are convenient memories. One thing they never forget is to use the Theocratic War Strategy, which is Watchtower's teaching that says they can lie to anybody who is not entitled to know the truth in their judgement. All is fair in Theocratic Warfare, including lying to investigators, judges, and other officials.
Is this found anywhere in print? If I could find this printed in a WT or book? If it is, it might just be the thing to crack the door of doubt on a parent.