Lina, in my humble opinion, in your story the blame is on the establishment to make fuss from this. If I am running a business like that, I would gladly give a Governor General a rain-check when his credit card bounces. And even if AMEX contacted the police, I would not let them enter the premises or had a waiter explain the situation to them "outside".
AMEX dispatchers just did what they trained them to do. They did not know the governor general themselves tried to use the card, but the business owner did know that.
Just my opinion though, I don't know the whole story, but your version does not make AMEX look bad at all, the opposite actually.