Answer:
It is very simple, if your house burns down, the evidence is there. All you need to do it look at a house that burnt down either completely or partially, but its easy to verify.
On the other hand, if you report that a necklace was stolen, it is really difficult to verify. Unless it is a unique jewel that is worth a ton of money, you could have simply given it away as a gift and then report it as stolen. The opportunities for insurance fraud are many when dealing with jewelry or other valuable objects that can be moved around easily.
The second question about different grants of authority refer to the organizational structure of a company. E.g. a salesperson in Best Buy is able to sell any item or items to regular customers. But sometimes a large order comes and the company must decide whether to discount the price or not, and then management kicks in and decides. The same happens to insurance agents. A company decides that some agents deal with policies that involve X amount of risk. If the level of risk is higher, they must work with other agents that are authorized to deal with high risk policies. It is basically a clearance level where employees are authorized up to this amount, and above that amount, other employees must be involved.
