There are very specific and limited instances in which an insurance company can deny coverage to a paying customer. Generally speaking, when an insurance company offers a policy to a customer, it is for a six-month period and covers anything which happens to the driver during that time. If the customer has an at-fault accident, the company must cover it, but may decide to drop the customer at the next renewal period. However, the company is still liable to pay all damages according to the policy for the accident which occurred during the coverage period.
However, there are exceptions to this rule. Generally, a company can refuse to pay a claim if it does not meet the covered events under the policy. Common exceptions or exclusions to policies include illegal actions and non-payment of premiums in a timely manner.
Violating the Law
If you use your car in a way which violates the law, you are often excluded from making claims under your insurance policy. For example, if an insured person allows his or her car to be used in the commission of a robbery (whether the insured driver was actually driving or not) the insurance company may claim an exclusion to the policy due to the fact that illegal acts are not covered. Similarly, many companies have DUI exclusions, which means that the company specifically puts in writing than any damages caused by an accident in which their insured driver had a blood alcohol content, or BAC, higher than the legal limit, are not covered.
Reckless and Careless Use of the Vehicle
Illegal acts are not the only ones excluded by insurance companies. In many cases, if it can be proven the insured driver of the vehicle deliberately used the vehicle in a careless or dangerous way, coverage may be excepted. For example, if a person allows someone to drive his or her car who is known not to have a driver's license, the auto insurance company may deny the claim based on this type of exclusion.
Failure to Pay Premiums
Non-payment is another issue often raised when insurance companies are expected to pay claims. If a person is behind on his or her premium payments, coverage may be affected. However, most states allow a "grace period" during which coverage is mandatory, even if the person is late paying the premium. If the person is outside the grace period in payment, however, coverage may be successfully denied.
Claims for Damages outside of your Policy Coverage
You may also be denied a claim based on the type of coverage you have. For example, if you drop your comprehensive coverage, the company will deny any claims made by you which would have been covered under your comprehensive policy. This includes theft, weather-related accidents, or accidents which are caused by things other than a collision with another car. Similarly, collision insurance coverage provides payment if your car is damaged in an accident in which you are at fault. If you drop your collision coverage, your company will not pay to have your vehicle repaired if you cause an accident.
Other than these general exceptions, there are few instances in which insurance companies can legally deny a claim. In general, if insurance companies offer you a policy and take your premium payment, they are legally obligated to pay any claims which are covered under the policy, including payment to other parties if you are at fault in the accident.
However, an insurance company can certainly "fight" a claim by another party if it feels that the other party was actually at fault in the accident. In some states, liability insurance can be assessed on a percentage basis; in other words, if both parties were at fault, a court can judge how much of the fault rests with each party.