Seriously, who needs to record someone without the knowledge of the person being recorded? That’s a big red flag, a perverted character, there’s no other explanation. Creepy Mark Zuckerberg allowed other creepy characters to share personal moments with him.
Except that the intent isn’t to remove the ability to film but to remove the risk of debris falling off riders. If the theme park really cared about filming, they probably could ban the glasses as well since they would be caught during the metal detection.