You completely fail at business strategy. If someone is yelling at you and is not satisfied with what is going on, are you going to deny them service at all? That's just a bad way to do business. Word of mouth advertising is worth a lot more than anything you could put on TV. If she goes and bitches to 10 friends about it, they'll bitch to 10 more friends, etc. In which case, they'll lose business. If you satisfy the customer, they will give you repeat business, which is what you want.
I mean, she was bitching because they couldn't accept her card. How many people are going to have Starbucks cards that go in there? Probably a small percentage of people. When you tell most of the people what Charlie told her, the majority will not throw a fit and will pay with cash or credit or whatever and go on their way (I'd inquire about why the cards aren't accepted, but that's as far as I'd go). You have those few though that will bitch and moan and it's easier to appease those people in the end than it is to turn them away (it's a job for the managers really since they are in charge). If they are making a really huge fucking scene especially.
