The part that got me was them saying the Mac address was an unique ID. No, mac addresses are not unique and can be faked. I tracked 680k devices at one job, macs are not unique!

Also, if they had the Mac address, they had to have captured data at the edge router which makes you wonder how much access does the spies have.

I can say, that big cellular networks have dedicated connections for government agencies that allows them to access any part of the cellular switch.