A female employee was fired for serious cause, because she had repeatedly and deceitfully transferred “bonus points” of clients to her personal loyalty card. Both at first instance and on appeal, the judges ruled that despite the severity of the misconduct, and taking into account the isolated character of the misconduct as well as the seniority of the employee, the dismissal for serious cause was not proportional to the misconduct. In so doing, the judges joined a certain tendency in the legal doctrine and case law, according to which when assessing a serious cause, the gravity of the therewith-associated sanction (i.e. the loss of employment without indemnity or period of notice) must be taken into account. Recently however, the Supreme Court ruled that by taking into account such proportionality, judges fail to appreciate the true essence of the term ‘serious cause’, which is defined as a misconduct which renders the continuation of the employment relationship immediately and definitely impossible. This does not allow for an evaluation to be made between the misconduct and the sanction.