Nissan Maxima Owners Manual: Precautions when starting and driving

WARNING

Do not leave children or adults who would normally require the assistance of others alone in your vehicle. Pets should also not be left alone. They could accidentally injure themselves or others through inadvertent operation of the vehicle. Also, on hot, sunny days, temperatures in a closed vehicle could quickly become high enough to cause severe or possibly fatal injuries to people or animals.
Closely supervise children when they are around cars to prevent them from playing and becoming locked in the trunk where they could be seriously injured.

Keep the car locked, with the rear seatback and trunk lid securely latched when not in use, and prevent children's access to car keys.