Liability, Dram Shop, and Permit Holder Responsibilities
Two kinds of exposure
Criminal and administrative penalties come first: selling to an underage person or to an intoxicated person is a charge against the individual and a citation against the permit, and the Division of Liquor Control can fine, suspend, or revoke. Civil exposure follows - an injured person suing the bar.
Ohio's dram shop statute
Ohio's dram shop liability is statutory (ORC 4399.18). It targets a person who knowingly sells or furnishes alcohol to an intoxicated person, or knowingly permits an intoxicated person to consume alcohol on premises under that person's control. The word knowingly is the battleground: the plaintiff must show the server knew, not merely that a reasonable server would have noticed. That makes your observation record the most valuable document in the file - the refusal log, the timestamps, the specific signs. Ohio generally does not recognize a broad negligence claim against a permit holder for serving an adult who later drives; the statute is the route, and it is narrow.
Serving minors is different
Sale to a minor is prohibited outright (ORC 4301.69), and an ID check is a defense only if you actually examined an acceptable document that reasonably appeared valid (ORC 4301.639). He looked 25 is not a defense. The permit holder is responsible for staff conduct during service.
Worked example
A guest is served three doubles, leaves, and injures a pedestrian. The bar's file shows no refusal log, no manager notification, and a tab with no timestamps. The plaintiff argues the server must have known. Without a record of what staff actually saw, the bar's best fact - that the guest seemed fine - disappears.
Traps
Thinking we didn't pour the last drink ends the analysis. Assuming liability exists only for minors. Believing a valid ID protects you against an intoxication claim.