Providing a valet service is convenient for your guests, but damaging a vehicle or property, or causing injury, is a very real risk associated with offering this service.
Obtain a general liability policy to protect your business from lawsuits by a third party. Be certain that a garagekeepers legal liability policy is also in effect with adequate limits to cover any physical damage to a guest's vehicle or other vehicles on-site. If you are using an independent valet service, obtain a certificate of insurance to verify they have the proper coverage with adequate limits. Also make sure that your business is named as an additional insured under their policy.
Note: Actual policies must be consulted for specific terms and conditions.