Trespassing on aerodromes

If any person trespasses on any land forming part of a Government aerodrome or an aerodrome licensed under regulations made under this Act, he shall be liable on summary conviction to a fine not exceeding five hundred dollars, provided that no person shall be liable to any penalty under this section unless it is proved that, at the material time, notices warning trespassers of their liability under this section were posted so as to be readily seen and read by members of the public, in such positions on or near thfe boundary of the aerodrome as appear to the court to be proper.