Insurable interest – the insured typically must directly suffer from the loss. Insurable interest must exist whether property insurance or insurance on a person is involved. The concept requires that the insured have a "stake" in the loss or damage to the life or property insured. What that "stake" is will be determined by the kind of insurance involved and the nature of the property ownership or relationship between the persons. The requirement of an insurable interest is what distinguishes insurance from gambling.
Large loss: The size of the loss must be meaningful from the perspective of the insured. Insurance premiums need to cover both the expected cost of losses, plus the cost of issuing and administering the policy, adjusting losses, and supplying the capital needed to reasonably assure that the insurer will be able to pay claims. For small losses, these latter costs may be several times the size of the expected cost of losses. There is hardly any point in paying such costs unless the protection offered has real value to a buyer.
Certain insurance products and practices have been described as rent-seeking by critics. That is, some insurance products or practices are useful primarily because of legal benefits, such as reducing taxes, as opposed to providing protection against risks of adverse events. Under United States tax law, for example, most owners of variable annuities and variable life insurance can invest their premium payments in the stock market and defer or eliminate paying any taxes on their investments until withdrawals are made. Sometimes this tax deferral is the only reason people use these products. Another example is the legal infrastructure which allows life insurance to be held in an irrevocable trust which is used to pay an estate tax while the proceeds themselves are immune from the estate tax.
When the policy of the vehicle owner and the policy of the permissive user have different limits, the matter becomes even more complicated. If the damages caused by the permissive user’s negligence exceed the owner’s liability limits, the policy of the permissive user might be tapped as secondary coverage, but usually only where the permissive user’s liability limits are higher than the owner’s liability limits.
There are certainly insurance carriers and policies that will not cover any driver not specifically named in the policy. Other relevant facts include where the “other driver” resides and if they are related to the insured. In general, if someone is living in the insured’s household and regularly drives the insured’s vehicle, many insurance carriers expect you to have that person named on the policy. They will need to undergo the same underwriting and qualification process as any other policyholder.