They're gonna have a cluster only to find out it's teenagers hanging with their friends
But seriously though, I'm the only one in my family to carry a phone in the park. Husband doesn't carry his ever because it's heavy, and 11yo just got her phone 2 months ago, no way in heck she'd take it in.
Maybe they have enough data gathered on app use in the park vs admissions a day, to know what the app to no app ratio is and can make some assumptions based on it.