Ace Caf hires Walker as a full-time dishwasher. During a lull in business, Walker decides to clean his bicycle chain in the dishwasher, which leaves an oily film in the dishwasher that gets on the caf's dishes and makes its customers sick. Assuming Walker is an employee, is the Caf vicariously liable to the customers for Walker's actions that made them sick? Explain why or why not.