Presumption respecting instruments of gaming found in places entered.

When any instrument of gaming is found in any place entered under the provisions of this Regulation or about the persons of any of those who are found therein, it shall be presumed until the contrary is proved, that such place is used as a common gaming-house and that the persons found therein were there present for the purpose of gaming, although no play was actually seen by the magistrate or police officer or by any one aiding in the entry.