Which of the following is NOT a duty after a loss in liability policies?

In liability policies, one key duty after a loss is for the insured to avoid making any restitution or payments that could affect the interests of the insurer without obtaining their consent. This is crucial because the insurer has the right to control claims and their disposition. If the insured makes restitution without the insurer's approval, it could complicate or undermine the claims process, possibly leading to a situation where the insurer is not liable for those costs or payments.

On the other hand, notifying the insurance company in writing, providing necessary assistance to the case, and forwarding applicable demands or notices are all essential duties following a loss. These actions ensure that the insurance company can adequately assess the situation, control the claim handling, and provide the necessary support in defense or settlement efforts. Thus, making restitution without the insurer's consent is not considered a duty required of the insured in the aftermath of a liability loss.