50. It is forbidden to hinder a person making an inquiry in accordance with this act, to mislead or attempt to mislead him by concealment or misrepresentation, to refuse to declare to him one’s surname, given names and address or to neglect to obey any order such person may give under this act or the regulations. Such person shall, if so required, produce a certificate attesting his authority signed by the president of the Board or a person thereunto authorized.