I just read about the Personal Area Network (PAN) for Shadowrun and they mention that some areas like airports, corp buildings or major metropolitain centers, require you to have your PAN turned active. Why? and how are they enforcing this?

I can see how in a corp building where you have to pass a guard point, they can scan and see if your PAN is open. If not, they politely ask you to turn it in active mode. I still don't know why they would need that.

But what about an airport or like a shopping mall? How can they control this?

So what are the motivations for such etiquette or rules and how can you make sure people respect it?