What behavior may indicate a passenger is intoxicated?

Spilling drinks can be a significant indicator of intoxication because it often reflects a lack of coordination and control that is commonly associated with being under the influence of alcohol. When individuals consume alcohol, their motor skills and judgment may be impaired, leading to clumsiness in their actions. Spilling drinks may also suggest that the passenger is experiencing difficulty with basic tasks like holding or managing items, a common symptom of intoxication.

While behaviors such as smiling excessively, talking loudly, or singing may also occur in intoxicated individuals, these actions alone may not provide a clear indication of intoxication without additional context. Smiling or talking loudly can be expressions of extroverted behavior that do not necessarily imply impairment. Similarly, singing can happen in social contexts without any relation to alcohol consumption. Therefore, spilling drinks stands out as a more concrete physical manifestation of possible intoxication.