Does Serena Williams response justify being slighted?

Here is the scenario. Serena William made a photo appearance in LA with fellow ATP player James Blake promoting a tournament called “Farmers Classic”.  A few days later, after leaving town for Florida and then returning to LA, she requested a free ticket to the tennis tournament. The organizers told her it would cost her $100 for the ticket. Below is Serena’s response on Twitter (click on the image). Do you think her response was justified? Or is she being picked on by the media?