When must you stop serving alcohol to guests?

As a responsible server, you should stop serving alcohol to guests when they look or act intoxicated. It is essential to monitor guests for signs of intoxication, such as slurred speech, unsteady movements, impaired judgment, or changes in behavior. Continuing to serve alcohol to an intoxicated person can contribute to unsafe situations, increase the risk of harm to the guest, and potentially lead to legal and liability issues for the establishment.
The other options mentioned (BAC of .10 or higher, not having a designated driver, finishing their second drink) can be factors to consider, but they alone may not be sufficient indicators of intoxication. It is important to rely on visible signs and behaviors to make informed decisions about when to stop serving alcohol to a guest.