1. TRY TO RESOLVE IT WITH SOMETHING THAT COMES EASILY TO YOU, THAT YOUR CUSTOMER VALUES. Whatever business you are in, you get your goods or services wholesale (free flights, even on a standby basis). Try to resolve the problem by offering something that has a high perceived value but is not so dear to you that it creates a large loss. The customer is ‘not’ always right, but the customer can write something about you on Yelp and, as it hurts you more to respond, they will ‘seem’ right to the public, who will only read one side of it all.
2. AVOID CALLING THE POLICE (of any kind) FOR A NON-CRIMINAL INCIDENT. Once you try to make the police force your own, and they step in with people who are trained to control others, you will have alienated your client past the point of no return. Worse yet, if the person flails and touches a police officer, he or she now gets a criminal record thanks to you and believe me, you will pay dearly for that. As stupid goes, this is the most stupid move a company can use against a client when the company is not at threat. A disagreement is never resolved when one party is fully armed and the other is afraid of arrest.