Often, when you use a parking lot, on the back of your parking slip or ticket there is a notice that the parking lot owner is not responsible for any damage to your car. Does this disclaimer operate to insulate the owner if your car is damaged? The answers vary widely from state to state, and depending on many circumstances.
In some states, courts have held that a preprinted ticket that includes an express waiver of liability can give sufficient notice to the customer that the parking lot was not taking responsibility for damage, and the parking lot owner is therefore not liable for damages caused to the car while the car was parked in a parking garage or lot. In some cases, courts have held that the waiver of liability does not apply where the customer did not see the waiver. For example, if the waiver is listed on a sign, but the customer did not see it, or would not normally pass the sign before leaving the lot or garage, then the waiver is not effective.
Other courts will only allow the waiver of liability to work where you do not give your car to an employee of the garage. However, in many states, courts reviewing parking tickets have held generally that these broad waivers of liability are void as against public policy. The courts reasoned that a parking garage acts as a professional bailer, and cannot waive its duties even where it expressly tells the customer that it is doing so.
However, even in states where the waiver of liability has an effect, those states generally agree that the waiver does not apply to damages to the car caused by the intentional or negligent actions of the garage or lot employees. The law generally does not allow you to waive liability for damages caused by your own negligence. If this were possible, then every business could just post a generic waiver of liability for everything they do, and customers would never have any recourse. Courts have almost universally held that such a waiver is ineffective, and customers need protection.