Any Water Bailiff, Constable, Watcher, or Officer of the Board, or any Police Officer, may enter and remain upon any Lands in the Vicinity of any River or of the Sea Coast during any Hour of the Day and Night for the Purpose of preventing a Breach of the Provisions of this or the recited Acts, or of detecting the Persons guilty of any Breach thereof, and no such Person entering and remaining upon such Lands as aforesaid shall be deemed to be a Trespasser: Provided always, that the Owner or Occupier of such Land may require such Person to quit, and such Person may on Refusal be proceeded against as a Trespasser, and shall be liable to the Penalties, unless he shall prove to the Satisfaction of the Sheriff or Justices before whom he is tried that he had reason to apprehend a Breach of the Law had been or was about to be committed.