I'm probably in the minority, but I change my MAC address at the airport quite often. For the airports that only give you 30 minutes of internet, if you change

I'm probably in the minority, but I change my MAC address at the airport quite often. For the airports that only give you 30 minutes of internet, if you change your MAC address, you can get repeated free sessions. Regardless, the main problem with what you suggest is that it would require going through everyone's phones, so you'd need to get a warrant, or many warrants, and it would be a very long drawn-out process.