You can simply equip those people with a tracker. Then it also works if they leave the stadium. Put them in their shoes and you dont need their cooperation either.
If they dont have any just put the persons picture on the stadium screens.
But my point would still stand even if I couldn't provide an example either. The burden of proving that a technology has no significant benefits should fall on the people trying to ban it.
There are countless things that our brains can do that are illegal to do with computers because our brains are so bad at it. Recording a phone call without notifying is illegal even though our brains remember it. Posting someone else's nudes without consent is illegal even though you can describe them from memory legally.
My eyes can't instantly recognise hundreds of strangers on the street and sync that data up with the global adtech database.