Age-shavers are my pet peeve. What I do with a suspected liar, I ask them what year they were born. As soon as they hesitate or stumble, you know you've caught them.
due diligence
NOUN
1Law Reasonable steps taken by a person in order to satisfy a legal requirement, especially in buying or selling something.
‘If trading is carried on, however, there is a duty to manage with due diligence in doing so.’