When observing a customer's appearance, which of the following may indicate intoxication?

A flushed face can be a physiological response to alcohol consumption, indicating that the individual may be intoxicated. When alcohol is ingested, it can cause blood vessels to expand, leading to a noticeable change in skin color, particularly on the face. This can be a sign that the person's body is reacting to the alcohol and may suggest that they have consumed a significant amount.

Other options, such as being well-groomed or wearing sunglasses indoors, do not provide reliable indicators of intoxication. A composed stance also does not imply intoxication, as it could suggest that the person is maintaining control over their physical state despite alcohol consumption. Therefore, recognizing a flushed face is vital in assessing a customer's level of intoxication.