Final answer:
When refusing service to a patron with dilated pupils and teeth grinding, approach the situation calmly, express concern for their well-being, and offer non-alcoholic assistance while abiding by establishment policies and state laws.
Step-by-step explanation:
If a patron approaches the bar displaying signs of intoxication or drug use, such as dilated pupils and teeth grinding, it is important for the safety of the individual and others to refuse service. One professional and respectful approach to this situation could be to calmly express concern for their well-being. You might say something like, 'I'm sorry, but I've noticed some signs that you might not be feeling well, and it wouldn't be responsible for me to serve you another drink. Can I get you some water or help you in some other way?' This approach prioritizes the person's safety while also maintaining a friendly and caring demeanor. It is also crucial to be aware of your establishment's policies on these matters, as well as the relevant state laws regarding service of alcohol.