What is a gratuity? What are the arguments for allowing gratuities? What are the

What is a gratuity? What are the arguments for allowing gratuities? What are the arguments against allowing gratuities? If you were a chief of police, what type of policy (if any) would you have concerning gratuities?
In the policing field, the concept or practice of gratuities are viewed differently by each law enforcement agency as to what constitutes a gratuity and what “gifts” can be accepted. Please remember that more than 18,000 different state, county, and local law enforcement agencies have different policies on this issue.