Liability insurances shift the financial risk of the loss of a damage from the person who is liable for the damage to the liability insurer. To avoid negligent behavior of the insured, the insurer provides different prevention tools in the insurance policy. The insurer will attach certain sanctions or rewards to certain behavior and certain circumstances in the general conditions of the insurance contract. This research raises the question of the effectiveness of these instruments. The hypothesis is that without knowledge of the insured of these sanctions or rewards, these sanctions and rewards will not form an additional incentive for careful behavior and they will have no preventive effect. Additionally, these prevention tools may undermine the protection of the insured. For this reason the legislature has limited the freedom of contract. This study examines the extent to which the legislature has limited the possibilities of the insurer to provide in prevention tools in de insurance policy. It assesses the extent to which the legislature may or may not succeed in its purpose to protect the insured, and on the other hand, where there are still possibilities for the insurer to fulfill its prevention task.