I'm not concerned about the show, I'm concerned about the people that it attracts, and their reaction to the rest of the event.
I would hate to see a family bring their children (of age or not) into the park, drawn in by the allure of more Potter that they couldn't see otherwise.
Then, said family freaks out because they didn't do their homework, and now their snowflakes have been traumatized by seeing blood and guts on their way to see their favorite wizard.
I'm sure most people would handle it fine, and understand what they're going to ahead of time; but, it only takes a few families to get the ear of the right media outlets.