No matter what the dealer states, they are liable for any and all damages. The employee in question, being an agent of the dealership, may have had a legitimate reason for being at the stealership. Now the other catch is if the employee did this on his own, and still the stealership is liable, because it was secured in a locked shop and the key should never been given to a service writer , unless he was a service manager. No matter how they want to cut this, the one that was given possession of the vehicle for service purposes, and under contract for service, is liable for all damages while service is being performed.