Arrange some activity to keep people on site for that last 30 minutes. Select sites that require minimal travel for the participants. Consider availability of taxi service or overnight lodging. Assign the clear responsibility to staff, the licensed vendor, or contracted security to see that any attendee who is intoxicated is identified and taken home safely. The licensee's premises are preferred to reduce liability risk.
Licensees are most clearly responsible for the conduct of patrons on the licensee's premises.
Avoid sites with long flights of stairs, wading pools, or any other hazard that could place a careless drinker at risk. The liability insurance must be endorsed to name the agency and the State of Oregon as additional insureds. A vendor or caterer who cannot readily meet this common requirement bears careful investigation before an exception is considered. Prior to the event, obtain certificates of insurance from the vendor to verify all required insurance coverages. If a licensed vendor is used for a small function, the insurance elements for Large Functions are recommended.