You should plan ahead for the misplacement of people's belongings as well as for the safety of the guests themselves. Easy to read signs being posted requiring guests to keep track of their things at your special event. These signs are more effective if placed by bathrooms and other rest areas. If the special event is providing a coat check area, staff should be there at all times. A sign advising guests that they leave their belongings at "their own risk" should be conspicuously placed throughout the facility. Despite all effort you put forth to have no lost items, guests will inevitably lose things. You should always plan for a secure lost and found area to store items until they are claimed.