9.—(1) Any person who does, without lawful authority, any act which prevents, obstructs or interferes with the transmission of signals between the in-vehicle unit installed in any motor vehicle and any ERP facility shall be guilty of an offence and shall be liable on conviction to a fine not exceeding $2,000 or to imprisonment for a term not exceeding 6 months or to both.
(2) It shall be a defence in any prosecution for a contravention of paragraph (1) for the person charged to prove to the satisfaction of the court that he did not know nor could reasonably have discovered the contravention referred to in the charge.