Read this one twice
Every other lesson in this module is about money. This one is about the part of the job where someone can be seriously hurt, and where the decision is yours, in the moment, with no time to consult anyone.
This lesson covers the part that is the same everywhere: how to see it coming, how to say it, and what to write down. The next lesson covers the part that is not the same everywhere — what the law where you work has to say about it, who can be held responsible, and why that answer is different in different states. Do both.
Stop thinking of it as an event
New bartenders imagine cutting someone off as a single dramatic moment: a person is visibly drunk, you announce a refusal, there is a scene.
That version is the failure case. It happens when nobody was paying attention for the previous two hours.