What is the defence of an employer in a sexual assault case?

First of all, Mr. Justice Dickson said in R v. The City of Sault St. Marie, found at (1978) 1978 CanLII 11 (SCC), 40 CCC (2nd) 353 at page 377: Where an employer is charged in respect of an act committed by an employee acting in the course of employment, the question will be whether the act took place without the accused's direction or approval, thus negating wilful involvement of the accused, and whether the accused exercised all reasonable care by establishing a proper system to prevent commission of the offence and by taking reasonable steps to ensure the effective operation of the system. The availability of the defence to a corporation will depend on whether such due diligence was taken by those who are the directing mind and will of the corporation whose acts are therefore in law the acts of the corporation itself.