but you have verified gaussmeter evidence that it is true?
Discussion
I don't think you'd use a gaussmeter but rather a mobile base station so you can measure the incoming pings
This was the approach used by SRLabs when testing their Blue Merle software for IMEI switching
https://github.com/srlabs/blue-merle?tab=readme-ov-file#imei-randomization
doesn't necessarily have to be mobile radio protocol, just something that someone can pick up, doesn't have to be strong, about 20 metres is probably enough, and that won't detect it