In a world with risk-neutral agents in which accidents occur with a positive probability, liability rules will only induce efficient behaviour if these rules impose the full (marginal) costs of an action on the parties. However, institutional restrictions or bilateral activity choices can prevent the full internalization of costs. A mechanism is proposed which guarantees an efficient outcome: monetary fines which are not related to the occurrence of an accident. Such a mechanism requires individuals to violate the standard of care in order to trigger the fine payments. Hence, efficiency requires an excessive standard.